顔写真

アキヤマ マサユキ
秋山 正幸
Masayuki Akiyama
所属
大学院理学研究科 天文学専攻 天文学講座
職名
教授
学位
  • 博士(理学)(京都大学)

  • 修士(理学)(京都大学)

e-Rad 研究者番号
50425401

経歴 3

  • 2017年4月 ~ 継続中
    東北大学 大学院理学研究科 天文学専攻 教授

  • 2008年4月 ~ 2017年3月
    東北大学 大学院理学研究科 天文学専攻 准教授

  • 2000年4月 ~ 2008年3月
    国立天文台ハワイ観測所 研究員

学歴 2

  • 京都大学 理学研究科 天文学専攻

    ~ 2000年3月31日

  • 京都大学 理学部 物理・宇宙物理学専攻

    ~ 1995年3月31日

委員歴 16

  • 東北大学ダイバーシティ・エクイティ・インクルージョン推進センター 副センター長

    2023年7月 ~ 継続中

  • TMT International Observatory Science Advisary Committee Chair

    2022年10月 ~ 継続中

  • 国立天文台 TMT 科学諮問委員会 委員長

    2020年9月 ~ 継続中

  • 仙台市天文台運営協議会 委員長

    2020年4月 ~ 継続中

  • 東北大学男女共同参画推進センター 副センター長

    2022年4月 ~ 2023年6月

  • TMT International Observatory Science Advisary Committee Member

    2011年4月 ~ 2022年9月

  • TMT推進小委員会 委員長

    2017年4月 ~ 2020年8月

  • 国立天文台すばる Time Allocation Committee 委員長

    2017年6月 ~ 2019年5月

  • すばる小委員会 委員

    2017年6月 ~ 2019年5月

  • Association of Universities for Research in Astronomy (AURA) Member Representative

    2016年5月 ~ 2019年4月

  • 日本天文学会 欧文論文誌編集委員

    2008年11月 ~ 2018年10月

  • 国立天文台光赤外専門委員会 委員

    2016年6月 ~ 2018年5月

  • 国立天文台すばる Time Allocation Committee 委員

    2015年6月 ~ 2017年5月

  • 国立天文台研究交流委員会 委員

    2012年4月 ~ 2017年3月

  • TMT推進小委員会 委員

    2011年4月 ~ 2017年3月

  • すばる小委員会 委員

    2010年8月 ~ 2014年7月

︎全件表示 ︎最初の5件までを表示

所属学協会 3

  • アメリカ天文学会

  • 日本天文学会

  • International Astronomical Union

研究キーワード 3

  • 光赤外線補償光学観測装置の開発

  • 超大質量ブラックホールの宇宙論的進化

  • 銀河の形成と進化

研究分野 1

  • 自然科学一般 / 天文学 / 銀河形成、進化、光赤外線観測装置

論文 227

  1. Black Hole Mass and Eddington-ratio Distributions of Less-luminous Quasars at z ∼ 4 in the Subaru Hyper Suprime-Cam Wide Field

    Wanqiu He, Masayuki Akiyama, Motohiro Enoki, Kohei Ichikawa, Kohei Inayoshi, Nobunari Kashikawa, Toshihiro Kawaguchi, Yoshiki Matsuoka, Tohru Nagao, Masafusa Onoue, Taira Oogi, Andreas Schulze, Yoshiki Toba, Yoshihiro Ueda

    Astrophysical Journal 962 (2) 2024年2月1日

    DOI: 10.3847/1538-4357/ad1518  

    ISSN:0004-637X

    eISSN:1538-4357

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    We investigate the black hole mass function (BHMF) and Eddington-ratio distribution function (ERDF) of broad-line active galactic nuclei (AGNs) at z = 4, based on a sample of 52 quasars with i < 23.2 at 3.50 ≤ z ≤ 4.25 from the Hyper Suprime-Cam Subaru Strategic Program S16A-Wide2 data set, and 1462 quasars with i < 20.2 in the same redshift range from the Sloan Digital Sky Survey data release 7 quasar catalog. Virial black hole (BH) masses of quasars are estimated using the width of the CIV 1549 Å line and the continuum luminosity at 1350 Å. To obtain the intrinsic broad-line AGN BHMF and ERDF, we correct for the incompleteness in the low-mass and/or low-Eddington-ratio ranges caused by the flux-limited selection. The resulting BHMF is constrained down to log M BH / M ⊙ ∼ 7.5 . In comparison with broad-line AGN BHMFs at z ∼ 2 in the literature, we find that the number density of massive SMBHs peaks at higher redshifts, consistent with the downsizing evolutionary scenario. Additionally, the resulting ERDF shows a negative dependence on BH mass, suggesting more massive SMBHs tend to accrete at lower-Eddington ratios at z = 4. With the derived intrinsic broad-line AGN BHMF, we also evaluate the active fraction of broad-line AGNs among the entire SMBH population at z = 4. The resulting active fraction may suggest a positive dependence on BH mass. Finally, we examine the time evolution of broad-line AGN BHMF between z = 4 and 6 through solving the continuity equation. The results suggest that the broad-line AGN BHMFs at z = 4-6 only show evolution in their normalization, but with no significant changes in their shape.

  2. Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). XVII. Black Hole Mass Distribution at z ∼ 6 Estimated via Spectral Comparison with Low-z Quasars

    Ayumi Takahashi, Yoshiki Matsuoka, Masafusa Onoue, Michael A. Strauss, Nobunari Kashikawa, Yoshiki Toba, Kazushi Iwasawa, Masatoshi Imanishi, Masayuki Akiyama, Toshihiro Kawaguchi, Akatoki Noboriguchi, Chien Hsiu Lee

    Astrophysical Journal 960 (2) 2024年1月1日

    DOI: 10.3847/1538-4357/ad045e  

    ISSN:0004-637X

    eISSN:1538-4357

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    We report the distribution of black hole (BH) masses and Eddingont ratios estimated for a sample of 131 low luminosity quasars in the early cosmic epoch (5.6 < z < 7.0). Our work is based on the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, which has constructed a low luminosity quasar sample down to M 1450 ∼ − 21 mag, exploiting the survey data of Hyper Suprime-Cam installed on Subaru Telescope. The discovery spectra of these quasars are limited to the rest-frame wavelengths of ∼1200-1400 Å, which contain no emission lines that can be used as BH mass estimators. In order to overcome this problem, we made use of low-z counterpart spectra from the Sloan Digital Sky Survey, which are spectrally matched to the high-z spectra in overlapping wavelengths. We then combined the C iv emission line widths of the counterparts with the continuum luminosity from the SHELLQs data to estimate BH masses. The resulting BH mass distribution has a range of ∼107-10 M ⊙, with most of the quasars having BH masses ∼108 M ⊙ with sub-Eddington accretion. The present study provides not only a new insight into normal quasars in the reionization epoch, but also a new promising way to estimate BH masses of high-z quasars without near-infrared spectroscopy.

  3. Quasar Luminosity Function at z = 7

    Yoshiki Matsuoka, Masafusa Onoue, Kazushi Iwasawa, Michael A. Strauss, Nobunari Kashikawa, Takuma Izumi, Tohru Nagao, Masatoshi Imanishi, Masayuki Akiyama, John D. Silverman, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Kohei Inayoshi, Rikako Ishimoto, Toshihiro Kawaguchi, Satoshi Kikuta, Kotaro Kohno, Yutaka Komiyama, Chien Hsiu Lee, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Atsushi J. Nishizawa, Masamune Oguri, Yoshiaki Ono, Taira Oogi, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Ayumi Takahashi, Tadafumi Takata, Masayuki Tanaka, Yoshiki Toba, Shiang Yu Wang, Takuji Yamashita

    Astrophysical Journal Letters 949 (2) 2023年6月1日

    DOI: 10.3847/2041-8213/acd69f  

    ISSN:2041-8205

    eISSN:2041-8213

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    We present the quasar luminosity function (LF) at z = 7, measured with 35 spectroscopically confirmed quasars at 6.55 < z < 7.15. The sample of 22 quasars from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, combined with 13 brighter quasars in the literature, covers an unprecedentedly wide range of rest-frame ultraviolet magnitudes over -28 < M 1450 < -23. We found that the binned LF flattens significantly toward the faint end populated by the SHELLQs quasars. A maximum likelihood fit to a double power-law model has a break magnitude M1450∗=-25.60-0.30+0.40, a characteristic density φ∗=1.35-0.30+0.47 Gpc-3 mag-1, and a bright-end slope β=-3.34-0.57+0.49, when the faint-end slope is fixed to α = -1.2 as observed at z ≤ 6. The overall LF shape remains remarkably similar from z = 4 to 7, while the amplitude decreases substantially toward higher redshifts, with a clear indication of an accelerating decline at z ≥ 6. The estimated ionizing photon density, 1048.2±0.1 s-1 Mpc-3, is less than 1% of the critical rate to keep the intergalactic medium ionized at z = 7, and thus indicates that quasars are not a major contributor to cosmic reionization.

  4. The cosmic web of X-ray active galactic nuclei seen through the eROSITA Final Equatorial Depth Survey (eFEDS)

    Johan Comparat, Wentao Luo, Andrea Merloni, Surhud More, Mara Salvato, Mirko Krumpe, Takamitsu Miyaji, William Brandt, Antonis Georgakakis, Masayuki Akiyama, Johannes Buchner, Tom Dwelly, Toshihiro Kawaguchi, Teng Liu, Tohru Nagao, Kirpal Nandra, John Silverman, Yoshiki Toba, Scott F. Anderson, Juna Kollmeier

    Astronomy and Astrophysics 673 2023年5月1日

    DOI: 10.1051/0004-6361/202245726  

    ISSN:0004-6361

    eISSN:1432-0746

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    Which galaxies in the general population turn into active galactic nuclei (AGNs) is a keystone of galaxy formation and evolution. Thanks to SRG/eROSITA- s contiguous 140 square degree pilot survey field, we constructed a large, complete, and unbiased soft X-ray flux-limited (FX > 6.5 × 10-15 erg s-1 cm-2) AGN sample at low redshift, 0.05 < z < 0.55. Two summary statistics, the clustering using spectra from SDSS-V and galaxy-galaxy lensing with imaging from HSC, are measured and interpreted with halo occupation distribution and abundance matching models. Both models successfully account for the observations. We obtain an exceptionally complete view of the AGN halo occupation distribution. The population of AGNs is broadly distributed among halos with a mean mass of 3.9-2.4+2.0 × 1012 Mo. This corresponds to a large-scale halo bias of b(z = 0.34) = 0.99-0.10+0.08. The central occupation has a large transition parameter, slog10(M) = 1.28 ± 0.2. The satellite occupation distribution is characterized by a shallow slope, asat = 0.73 ± 0.38. We find that AGNs in satellites are rare, with fsat < 20%. Most soft X-ray-selected AGNs are hosted by central galaxies in their dark matter halo. A weak correlation between soft X-ray luminosity and large-scale halo bias is confirmed (3.3s). We discuss the implications of environmental-dependent AGN triggering. This study paves the way toward fully charting, in the coming decade, the coevolution of X-ray AGNs, their host galaxies, and dark matter halos by combining eROSITA with SDSS-V, 4MOST, DESI, LSST, and Euclid data.

  5. eROSITA Final Equatorial-Depth Survey (eFEDS) eFEDS X-ray view of WERGS radio galaxies selected by the Subaru/HSC and VLA/FIRST survey

    Kohei Ichikawa, Takuji Yamashita, Andrea Merloni, Junyao Li, Teng Liu, Mara Salvato, Masayuki Akiyama, Riccardo Arcodia, Tom Dwelly, Xiaoyang Chen, Masatoshi Imanishi, Kohei Inayoshi, Toshihiro Kawaguchi, Taiki Kawamuro, Mitsuru Kokubo, Yoshiki Matsuoka, Tohru Nagao, Malte Schramm, Hyewon Suh, Masayuki Tanaka, Yoshiki Toba, Yoshihiro Ueda

    ASTRONOMY & ASTROPHYSICS 672 2023年4月

    出版者・発行元:EDP SCIENCES S A

    DOI: 10.1051/0004-6361/202244271  

    ISSN:0004-6361

    eISSN:1432-0746

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    yWe constructed the eROSITA X-ray catalog of radio galaxies discovered by the WERGS survey, made by cross-matching the wide area Subaru/Hyper Suprime-Cam (HSC) optical survey and VLA/FIRST 1.4 GHz radio survey. We report finding 393 eROSITA detected radio galaxies in the 0.5 2 keV band in the eFEDS field covering 140 deg(2). Thanks to the wide and medium depth eFEDS X-ray survey down to f(0.5-2 keV) = 6 :5 x10-(15) erg s(-1) cm(-2), the sample contains the rare and most X-ray luminous radio galaxies above the knee of the X-ray luminosity function, spanning 44 < log(L0.5-2keV ((abs,corr)) /ergs(-1)) < 46:5 at 1 < z < 4. The sample also contains the sources around and below the knee for the sources 41 < log(L0.5-2keV((abs,corr)) /ergs(-1) < 45 at z < 1. Based on the X-ray properties obtained by the spectral fitting, 37 sources show obscured active galactic nucleus (AGN) signatures with log(N-H =cm(-2)) > 22. These obscured and radio AGN reside in 0:4 < z < 3:2, indicating that they are obscured counterparts of the radio-loud quasar, which were missed in the previous optical quasar surveys. By combining radio and X-ray luminosities, we also investigated the jet production efficiency eta(jet) = eta P-rad(jet) / L-AGN;bol by utilizing the jet power of P-jet. We find that there are 14 sources with extremely high jet production efficiency at eta(jet) approximate to 1. This high eta(jet) value might be a result of the decreased radiation efficiency of eta(rad) < 0:1, due to the low accretion rate for those sources, and /or of the boosting due to the decline of LAGN;bol by a factor of 10 100 by keeping Pjet constant in the previous Myr, indicating the experience of the AGN feedback. Finally, inferring the BH masses from the stellar mass, we find that X-ray luminous sources show the excess of the radio emission with respect to the value estimated from the fundamental plane. This radio emission excess cannot be explained by the Doppler boosting alone, and therefore the disk-jet connection of X-ray luminous eFEDS-WERGS is fundamentally different from the conventional fundamental plane which mainly covers the low-accretion regime.

  6. The Obscured Fraction of Quasars at Cosmic Noon

    Bovornpratch Vijarnwannaluk, Masayuki Akiyama, Malte Schramm, Yoshihiro Ueda, Yoshiki Matsuoka, Yoshiki Toba, Marcin Sawicki, Stephen Gwyn, Janek Pflugradt

    The Astrophysical Journal 2022年12月1日

    DOI: 10.3847/1538-4357/ac9c07  

  7. Optical IFU observations of GOALS sample with KOOLS-IFU on Seimei Telescope: Initial results of nine U/LIRGs at <i>z</i> &amp;lt; 0.04

    Yoshiki Toba, Satoshi Yamada, Kazuya Matsubayashi, Koki Terao, Aoi Moriya, Yoshihiro Ueda, Kouji Ohta, Aoi Hashiguchi, Kazuharu G Himoto, Hideyuki Izumiura, Kazuma Joh, Nanako Kato, Shuhei Koyama, Hiroyuki Maehara, Rana Misato, Akatoki Noboriguchi, Shoji Ogawa, Naomi Ota, Mio Shibata, Nozomu Tamada, Anri Yanagawa, Naoki Yonekura, Tohru Nagao, Masayuki Akiyama, Masaru Kajisawa, Yoshiki Matsuoka

    Publications of the Astronomical Society of Japan 74 (6) 1356-1367 2022年12月1日

    出版者・発行元:Oxford University Press (OUP)

    DOI: 10.1093/pasj/psac073  

    ISSN:0004-6264

    eISSN:2053-051X

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    Abstract We present ionized gas properties of nine local ultra/luminous infrared galaxies (U/LIRGs) at z &amp;lt; 0.04 through Integral Field Unit (IFU) observations with KOOLS-IFU on the Seimei Telescope. The observed targets are drawn from the Great Observatories All-sky LIRG Survey (GOALS), covering a wide range of merger stages. We successfully detect emission lines such as Hβ, [O iii]λ5007, Hα, [N ii]λλ6549, 6583, and [S ii]λλ6717, 6731 with a spectral resolution of R = 1500–2000, which provides (i) a spatially resolved (∼200–700 pc) moment map of ionized gas and (ii) diagnostics for an active galactic nucleus (AGN) within the central ∼3–11 kpc in diameter for our sample. We find that the [O iii] outflow that is expected to be driven by an AGN tends to be stronger (i) towards the galactic center and (ii) as a sequence of the merger stage. In particular, the outflow strength in the late-stage (stage D) mergers is about 1.5 times stronger than that in the early-state (stage B) mergers, which indicates that galaxy mergers could induce AGN-driven outflow and play an important role in the co-evolution of galaxies and supermassive black holes.

  8. H1821+643: The Most X-Ray and Infrared Luminous Active Galactic Nucleus (AGN) in the Swift/BAT Survey in the Process of Rapid Stellar and Supermassive Black Hole Mass Assembly

    Hikaru Fukuchi, Kohei Ichikawa, Masayuki Akiyama, Claudio Ricci, Sunmyon Chon, Mitsuru Kokubo, Ang Liu, Takuya Hashimoto, Takuma Izumi

    ASTROPHYSICAL JOURNAL 940 (1) 2022年11月

    出版者・発行元:IOP Publishing Ltd

    DOI: 10.3847/1538-4357/ac9304  

    ISSN:0004-637X

    eISSN:1538-4357

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    H1821+643 is the most X-ray luminous nonbeamed active galactic nucleus (AGN) of L (14-150 keV) = 5.2 x 10(45) erg s(-1) in the Swift/Burst Alert Telescope (BAT) ultrahard X-ray survey, and it is also a hyperluminous infrared (IR) galaxy L (IR) = 10(13.2) L (& ODOT;) residing in the center of a massive galaxy cluster, which is a unique environment achieving the rapid mass assembly of black holes (BH) and host galaxies in the local universe. We decompose the X-ray to IR spectral energy distribution (SED) into the AGN and starburst component using the SED-fitting tool CIGALE-2022.0 and show that H1821+643 consumes a large amount of cold gas ( M?con 7 to 10(2) K thanks to [O i] 63 mu m, which is a main coolant in low temperature range (10(4) to 10(2) K) with a cooling rate of M?cool=3.2x105M & ODOT;yr-1

  9. XXL-HSC: Link between AGN activity and star formation in the early Universe (<i>z</i> ⩾ 3.5)

    E. Pouliasis, G. Mountrichas, I. Georgantopoulos, A. Ruiz, R. Gilli, E. Koulouridis, M. Akiyama, Y. Ueda, C. Garrel, T. Nagao, S. Paltani, M. Pierre, Y. Toba, C. Vignali

    Astronomy &amp; Astrophysics 667 A56-A56 2022年11月

    出版者・発行元:EDP Sciences

    DOI: 10.1051/0004-6361/202243502  

    ISSN:0004-6361

    eISSN:1432-0746

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    In this work, our aim is to investigate the star formation rate (SFR) of the host galaxies of active galactic nuclei (AGNs) in the early Universe. To this end, we constructed a sample of 149 luminous (L<sub>2 − 10 keV</sub> &gt; 10<sup>44</sup> erg s<sup>−1</sup>) X-ray AGNs at z ≥ 3.5 selected in three fields with different depths and observed areas from the Chandra COSMOS Legacy survey, XMM-XXL North, and eROSITA Final Equatorial-Depth Survey. We built their spectral energy distributions (SED) using the available multi-wavelength photometry from X-rays up to the far-IR. Then, we estimated the stellar mass, M<sub>*</sub>, and the SFR of the AGNs using the X-CIGALE SED fitting algorithm. After applying several quality criteria, we ended up with 89 high-z sources. More than half (55%) of the X-ray sample have spectroscopic redshifts. Based on our analysis, our high-z X-ray AGNs live in galaxies with a median M<sub>*</sub> = 5.6 × 10<sup>10</sup>M<sub>⊙</sub> and SFR<sub>*</sub> ≈ 240 M<sub>⊙</sub>yr<sup>−1</sup>. The majority of the high-z sources (∼89%) were found inside or above the main sequence (MS) of star-forming galaxies. Estimations of the normalised SFR, SFR<sub>NORM</sub>, defined as the ratio of the SFR of AGNs, to the SFR of MS galaxies, show that the SFR of AGNs is enhanced by a factor of ∼1.8 compared to non-AGN star-forming systems. Combining our results with previous studies at lower redshifts, we confirmed that SFR<sub>NORM</sub> does not evolve with redshift. Using the specific black hole accretion rate (i.e. L<sub>X</sub> divided by M<sub>*</sub>), λ<sub>BHAR</sub>, which can be used as a tracer of the Eddington ratio, we found that the majority of AGNs that lie inside or above the MS have higher specific accretion rates compared to sources below the MS. Finally, we found indications that the SFR of the most massive AGN host galaxies (log (M<sub>*</sub>/M<sub>⊙</sub>) &gt; 10<sup>11.5 − 12</sup>) remains roughly constant as a function of M<sub>*</sub>, in agreement with the SFR of MS star-forming galaxies.

  10. Finding of a Population of Active Galactic Nuclei Showing a Significant Luminosity Decline in the Past ∼103–104 yr

    Janek Pflugradt, Kohei Ichikawa, Masayuki Akiyama, Mitsuru Kokubo, Bovornpractch Vijarnwannaluk, Hirofumi Noda, Xiaoyang Chen

    The Astrophysical Journal 938 (1) 75-75 2022年10月1日

    出版者・発行元:American Astronomical Society

    DOI: 10.3847/1538-4357/ac8ff3  

    ISSN:0004-637X

    eISSN:1538-4357

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    Abstract Recent observations have revealed an interesting active galactic nucleus (AGN) subclass that shows strong activity at large scales (∼1 kpc) but weaker at small scales (&lt;10 pc), suggesting a strong change in the mass accretion rate of the central engine in the past 10<sup>3</sup>–10<sup>4</sup> yr. We systematically search for such declining or fading AGNs by cross-matching the Sloan Digital Sky Survey type 1 AGN catalog at z &lt; 0.4, covering the [O iii] λ5007 emission line, which is a tracer for the narrow-line region emission, with the Wide-field Infrared Survey Explorer (WISE) mid-infrared (MIR) catalog covering the emissions from the dusty tori. Out of the 7653 sources, we found 57 AGNs whose bolometric luminosities estimated from the MIR band are at least one order of magnitude fainter than those estimated from the [O iii] λ5007 emission line. This luminosity-declining AGN candidate population shows four important properties: (1) the past AGN activity estimated from the [O iii] λ5007 line reaches approximately the Eddington limit; (2) more than 30% of the luminosity-declining AGN candidates show a large absolute variability of ΔW1 &gt; 0.45 mag in the previous ∼10 yr at the WISE 3.4 μm band; (3) the median ratio of log([N ii] λ6584/Hαλ6563) = −0.52, suggesting a lower gas metallicity and/or higher ionization parameter compared to other AGN populations; and (4) the second-epoch spectra of the population indicate a spectral type change for 15% of the sources. This population provides insights on the possible connection between the luminosity decline that started ∼10<sup>3</sup>–10<sup>4</sup> yr ago and the decline in the recent 10 yr.

  11. Aliasing effect of rolling shutter readout in laser guide star wavefront sensing

    Hajime Ogane, Masayuki Akiyama, Jesse Cranney, François Rigaut, Noelia Martínez Rey, Céline d'Orgeville, Yosuke Minowa, Yoshito . Ono

    Adaptive Optics Systems VIII 2022年8月30日

    出版者・発行元:SPIE

    DOI: 10.1117/12.2629689  

  12. High contrast and high angular imaging at Subaru Telescope

    Olivier Guyon, Kyohoon Ahn, Masayuki Akiyama, Thayne Currie, Vincent Deo, Takashi Hattori, Tomoyuki Kudo, Julien Lozi, Yosuke Minowa, Yoshito . Ono, Nour Skaf, Motohide Tamura, Sebastien Vievard

    Adaptive Optics Systems VIII 2022年8月30日

    出版者・発行元:SPIE

    DOI: 10.1117/12.2630534  

  13. ULTIMATE-START: current status of the Subaru Tomography Adaptive optics Research experimenT

    Koki Terao, Masayuki Akiyama, Yosuke Minowa, Yoshito Ono, Hajime Ogane, Takumi Akasawa, Shin Oya, Tomoyasu Yamamuro

    Adaptive Optics Systems VIII 2022年8月30日

    出版者・発行元:SPIE

    DOI: 10.1117/12.2629652  

  14. Optical design of the Wavefront sensing in the ULTIMATE-Subaru Ground Layer Adaptive Optics system

    Yoko Tanaka, Yosuke Minowa, Yoshito . Ono, Koki Terao, Hiroshige Yoshida, Masayuki Akiyama, Noelia Martínez Rey, Nicholas Herrald, Céline d'Orgeville, François Rigaut, Israel Vaughn, David Chandler, Dionne Haynes, Warrick Schofield

    Adaptive Optics Systems VIII 2022年8月30日

    出版者・発行元:SPIE

    DOI: 10.1117/12.2629581  

  15. ULTIMATE-Subaru: GLAO preliminary design overview

    Yosuke Minowa, Yoshito Ono, Yoko Tanaka, Hiroshige Yoshida, Koki Terao, Yusei Koyama, Sadman Ali, Ichi Tanaka, Takashi Hattori, Hirofumi Okita, Yutaka Hayano, Shin Oya, Kentaro Motohara, Kenshi Yanagisawa, Michitoshi Yoshida, Masayuki Akiyama, Tadayuki Kodama, Hajime Ogane, Masahiro Konishi, Noelia Martínez Rey, Nicholas Herrald, Céline d'Orgeville, François Rigaut, Israel Vaughn, David Chandler, Dionne Haynes, Warrick Schofield, Shiang-Yu Wang, Chi-Yi Chou, Masahiko Kimura

    Proceedings of SPIE, Adaptive Optics Systems VIII 12185 2022年8月30日

    出版者・発行元:SPIE

    DOI: 10.1117/12.2629749  

  16. NINJA : an LTAO assisted optical and near-infrared spectrograph of Subaru Telescope

    Chihiro Tokoku, Shinobu Ozaki, Takashi Moriya, Kenshi Yanagisawa, Kentaro Motohara, Masami Ouchi, Nozomu Tominaga, Masaomi Tanaka, Yoshito Ono, Yosuke Minowa, Yutaka Hayano, Yusei Koyama, Sadman Ali, Masayuki Tanaka, Masayuki Akiyama, Tohru Nagao, Yoshiki Matsuoka, Kosuke Kushibiki, Shogo Homan, Akino Yasuda, Michitoshi Yoshida

    Ground-based and Airborne Instrumentation for Astronomy IX 2022年8月29日

    出版者・発行元:SPIE

    DOI: 10.1117/12.2627749  

  17. Dissecting Nearby Galaxies with piXedfit. II. Spatially Resolved Scaling Relations among Stars, Dust, and Gas

    Abdurro’uf, Yen-Ting Lin, Hiroyuki Hirashita, Takahiro Morishita, Sandro Tacchella, Po-Feng Wu, Masayuki Akiyama, Tsutomu T. Takeuchi

    The Astrophysical Journal 2022年8月1日

    DOI: 10.3847/1538-4357/ac7da4  

  18. On the Connection between Supermassive Black Holes and Galaxy Growth in the Reionization Epoch

    Junyao Li, John D. Silverman, Takuma Izumi, Wanqiu He, Masayuki Akiyama, Kohei Inayoshi, Yoshiki Matsuoka, Masafusa Onoue, Yoshiki Toba

    The Astrophysical Journal Letters 2022年5月1日

    DOI: 10.3847/2041-8213/ac6de8  

  19. The eROSITA Final Equatorial-Depth Survey (eFEDS) A multiwavelength view of WISE mid-infrared galaxies/active galactic nuclei

    Yoshiki Toba, Teng Liu, Tanya Urrutia, Mara Salvato, Junyao Li, Yoshihiro Ueda, Marcella Brusa, Naomichi Yutani, Keiichi Wada, Atsushi J. Nishizawa, Johannes Buchner, Tohru Nagao, Andrea Merloni, Masayuki Akiyama, Riccardo Arcodia, Bau-Ching Hsieh, Kohei Ichikawa, Masatoshi Imanishi, Kaiki T. Inoue, Toshihiro Kawaguchi, Georg Lamer, Kirpal Nandra, John D. Silverman, Yuichi Terashima

    ASTRONOMY & ASTROPHYSICS 661 2022年5月

    出版者・発行元:EDP SCIENCES S A

    DOI: 10.1051/0004-6361/202141547  

    ISSN:0004-6361

    eISSN:1432-0746

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    Aims. We investigate the physical properties - such as the stellar mass (M-*), star-formation rate, infrared (IR) luminosity (L-IR), X-ray luminosity (L-X), and hydrogen column density (N-H) - of mid-IR (MIR) galaxies and active galactic nuclei (AGN) at z < 4 in the 140 deg(2) field observed by eROSITA on SRG using the Performance-and-Verification-Phase program named the eROSITA Final Equatorial Depth Survey (eFEDS).Methods. By cross-matching the WISE 22 mu m (W4)-detected sample and the eFEDS X-ray point-source catalog, we find that 692 extragalactic objects are detected by eROSITA. We have compiled a multiwavelength dataset extending from X-ray to far-IR wavelengths. We have also performed (i) an X-ray spectral analysis, (ii) spectral-energy-distribution fitting using X-CIGALE, (iii) 2D image-decomposition analysis using Subaru Hyper Suprime-Cam images, and (iv) optical spectral fitting with QSFit to investigate the AGN and host-galaxy properties. For 7088 WISE 22 tim objects that are undetected by eROSITA, we have performed an X-ray stacking analysis to examine the typical physical properties of these X-ray faint and probably obscured objects.Results. We find that (i) 82% of the eFEDS-W4 sources are classified as X-ray AGN with log L-X > 42 erg s(-1); (ii) 67 and 24% of the objects have log (L-IR/L-circle dot) > 12 and 13, respectively; (iii) the relationship between L-X and the 6 mu m luminosity is consistent with that reported in previous works; and (iv) the relationship between the Eddington ratio and N-H for the eFEDS-W4 sample and a comparison with a model prediction from a galaxy-merger simulation indicates that approximately 5.0% of the eFEDS-W4 sources in our sample are likely to be in an AGN-feedback phase, in which strong radiation pressure from the AGN blows out the surrounding material from the nuclear region.Conclusions. Thanks to the wide area coverage of eFEDS, we have been able to constrain the ranges of the physical properties of the WISE 22 mu m-selected sample of AGNs at z < 4, providing a benchmark for forthcoming studies on a complete census of MIR galaxies selected from the full-depth eROSITA all-sky survey.

  20. Multiline Assessment of Narrow-line Regions in z ∼ 3 Radio Galaxies

    Koki Terao, Tohru Nagao, Kyoko Onishi, Kenta Matsuoka, Masayuki Akiyama, Yoshiki Matsuoka, Takuji Yamashita

    The Astrophysical Journal 929 (1) 51-51 2022年4月1日

    出版者・発行元:American Astronomical Society

    DOI: 10.3847/1538-4357/ac5b71  

    ISSN:0004-637X

    eISSN:1538-4357

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    Abstract In this paper, we use high-quality rest-UV spectra of three radio galaxies at z ∼ 3 observed with the FORS2 camera on the Very Large Telescope to measure the flux of several emission lines, including relatively faint ones, such as N iv]λ1486, O iii]λ1663, and [Ne iv]λ2424. Additionally, we collect fluxes of faint rest-UV emission lines in 12 z ∼ 3 radio galaxies from the literature. Previously, physical and chemical properties of narrow-line regions (NLRs) in high-z active galactic nuclei (AGNs) have been investigated mostly by using only strong rest-UV emission lines (e.g., N vλ1240, C ivλ1549, He iiλ1640, and C iii]λ1909). Such strong-line diagnostics are based on various assumptions due to the limitation in the number of available emission-line constraints. In this work, both physical and chemical properties of NLR clouds in each object are estimated by fitting detailed photoionization models to the measured emission-line fluxes. We confirm that the metallicity of NLRs in AGNs at z ∼ 3 is solar or supersolar, without assumptions about the gas density and ionization parameter thanks to the constraints from the faint emission lines. This result suggests that high-z radio galaxies are already chemically mature at z ∼ 3.

  21. Subaru High- z Exploration of Low-luminosity Quasars (SHELLQs). XVI. 69 New Quasars at 5.8 &lt; z &lt; 7.0

    Yoshiki Matsuoka, Kazushi Iwasawa, Masafusa Onoue, Takuma Izumi, Nobunari Kashikawa, Michael A. Strauss, Masatoshi Imanishi, Tohru Nagao, Masayuki Akiyama, John D. Silverman, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Rikako Ishimoto, Toshihiro Kawaguchi, Nanako Kato, Satoshi Kikuta, Kotaro Kohno, Yutaka Komiyama, Chien Hsiu Lee, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Atsushi J. Nishizawa, Masamune Oguri, Yoshiaki Ono, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Ayumi Takahashi, Tadafumi Takata, Masayuki Tanaka, Yoshiki Toba, Yousuke Utsumi, Shiang Yu Wang, Takuji Yamashita

    Astrophysical Journal, Supplement Series 259 (1) 18-18 2022年3月

    出版者・発行元:American Astronomical Society

    DOI: 10.3847/1538-4365/ac3d31  

    ISSN:0067-0049

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    We present the spectroscopic discovery of 69 quasars at 5.8 < z < 7.0, drawn from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) imaging survey data. This is the 16th publication from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, and it completes identification of all but the faintest candidates (i.e., i-band dropouts with z AB < 24 and y-band detections, and z-band dropouts with y AB < 24) with Bayesian quasar probability PQB>0.1 in the HSC-SSP third public data release (PDR3). The sample reported here also includes three quasars with PQB<0.1 at z ∼6.6, which we selected in an effort to completely cover the reddest point sources with simple color cuts. The number of high-z quasars discovered in SHELLQs has now grown to 162, including 23 type II quasar candidates. This paper also presents identification of seven galaxies at 5.6 < z < 6.7, an [O iii] emitter at z = 0.954, and 31 Galactic cool stars and brown dwarfs. High-z quasars and galaxies compose 75% and 16%, respectively, of all the spectroscopic SHELLQs objects that pass our latest selection algorithm with the PDR3 photometry. That is, a total of 91% of the objects lie at z > 5.6. This demonstrates that the algorithm has very high efficiency, even though we are probing an unprecedentedly low luminosity population down to M 1450 ∼-21 mag.

  22. XXL-HSC: An updated catalogue of high-redshift (<i>z</i> ≥ 3.5) X-ray AGN in the XMM-XXL northern field

    E. Pouliasis, I. Georgantopoulos, A. Ruiz, R. Gilli, E. Koulouridis, M. Akiyama, Y. Ueda, L. Chiappetti, C. Garrel, C. Horellou, T. Nagao, S. Paltani, M. Pierre, Y. Toba, C. Vignali

    Astronomy &amp; Astrophysics 658 A175-A175 2022年2月

    出版者・発行元:EDP Sciences

    DOI: 10.1051/0004-6361/202142059  

    ISSN:0004-6361

    eISSN:1432-0746

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    X-rays offer a reliable method to identify active galactic nuclei (AGNs). However, in the high-redshift Universe, X-ray AGNs are poorly sampled due to their relatively low space density and the small areas covered by X-ray surveys. In addition to wide-area X-ray surveys, it is important to have deep optical data in order to locate the optical counterparts and determine their redshifts. In this work, we built a high-redshift (z ≥ 3.5) X-ray-selected AGN sample in the XMM-XXL northern field using the most updated [0.5–2 keV] catalogue along with a plethora of new spectroscopic and multi-wavelength catalogues, including the deep optical Subaru Hyper Suprime-Cam (HSC) data, reaching magnitude limits i ∼ 26 mag. We selected all the spectroscopically confirmed AGN and complement this sample with high-redshift candidates that are HSC g- and r-band dropouts. To confirm the dropouts, we derived their photometric redshifts using spectral energy distribution techniques. We obtained a sample of 54 high-z sources (28 with spec-z), the largest in this field so far (almost three times larger than in previous studies), and we estimated the possible contamination and completeness. We calculated the number counts (log N-log S) in different redshift bins and compared our results with previous studies and models. We provide the strongest high-redshift AGN constraints yet at bright fluxes (f<sub>0.5 − 2 keV</sub> &gt; 10<sup>−15</sup> erg s<sup>−1</sup> cm<sup>−2</sup>). The samples of z ≥ 3.5, z ≥ 4, and z ≥ 5 are in agreement with an exponential decline model similar to that witnessed at optical wavelengths. Our work emphasises the importance of using wide-area X-ray surveys with deep optical data to uncover high-redshift AGNs.

  23. Dissecting Nearby Galaxies with piXedfit. I. Spatially Resolved Properties of Stars, Dust, and Gas as Revealed by Panchromatic SED Fitting

    Abdurro’uf, Yen-Ting Lin, Hiroyuki Hirashita, Takahiro Morishita, Sandro Tacchella, Masayuki Akiyama, Tsutomu T. Takeuchi, Po-Feng Wu

    The Astrophysical Journal 2022年2月1日

    DOI: 10.3847/1538-4357/ac439a  

  24. A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). IV. Rapidly Growing (Super)Massive Black Holes in Extremely Radio-loud Galaxies

    Kohei Ichikawa, Takuji Yamashita, Yoshiki Toba, Tohru Nagao, Kohei Inayoshi, Maria Charisi, Wanqiu He, Alexander Y. Wagner, Masayuki Akiyama, Bovornpratch Vijarnwannaluk, Xiaoyang Chen, Masaru Kajisawa, Taiki Kawamuro, Chien-Hsiu Lee, Yoshiki Matsuoka, Malte Schramm, Hyewon Suh, Masayuki Tanaka, Hisakazu Uchiyama, Yoshihiro Ueda, Janek Pflugradt, Hikaru Fukuchi

    The Astrophysical Journal 921 (1) 51-51 2021年11月1日

    出版者・発行元:American Astronomical Society

    DOI: 10.3847/1538-4357/ac1b26  

    ISSN:0004-637X

    eISSN:1538-4357

  25. Ionizing radiation from AGNs at z &gt; 3.3 with the Subaru Hyper Suprime-Cam Survey and the CFHT Large Area U-band Deep Survey (CLAUDS)

    Ikuru Iwata, Marcin Sawicki, Akio K Inoue, Masayuki Akiyama, Genoveva Micheva, Toshihiro Kawaguchi, Nobunari Kashikawa, Stephen Gwyn, Stephane Arnouts, Jean Coupon, Guillaume Desprez

    Monthly Notices of the Royal Astronomical Society 2021年9月25日

    出版者・発行元:Oxford University Press ({OUP})

    DOI: 10.1093/mnras/stab2742  

  26. The eROSITA Final Equatorial-Depth Survey (eFEDS): An X-ray-bright, extremely luminous infrared galaxy at z=1.87

    Yoshiki Toba, Marcella Brusa, Teng Liu, Johannes Buchner, Yuichi Terashima, Tanya Urrutia, Mara Salvato, Masayuki Akiyama, Riccardo Arcodia, Andy D. Goulding, Yuichi Higuchi, Kaiki T. Inoue, Toshihiro Kawaguchi, Georg Lamer, Andrea Merloni, Tohru Nagao, Yoshihiro Ueda, Kirpal Nandra

    ASTRONOMY & ASTROPHYSICS 649 2021年5月

    出版者・発行元:EDP SCIENCES S A

    DOI: 10.1051/0004-6361/202140317  

    ISSN:0004-6361

    eISSN:1432-0746

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    In this study, we investigate the X-ray properties of WISE J090924.01+000211.1 (WISEJ0909+0002), an extremely luminous infrared (IR) galaxy (ELIRG) at zspec = 1 :871 in the eROSITA Final Equatorial-Depth Survey. WISEJ0909+0002 is a WISE 22 -m source, located in the GAMA-09 field, which was detected by eROSITA during the performance and verification phase. The corresponding optical spectrum indicates that this object is a type-1 active galactic nucleus (AGN). Observations from eROSITA combined with Chandra and XMM-Newton archival data indicate a very luminous (L (2-10 keV) = (2 :1 X 0 :2) X 1045 erg s 1) unobscured AGN with a power-law photon index of = 1 :73+0:16 0:15 and an absorption hydrogen column density of log (NH =cm 2) < 21 :0. The IR luminosity was estimated to be LIR = (1:79X 0:09) X 1014 L fi from spectral energy distribution modeling based on 22 photometric data points (X-ray to far-IR) with X-CIGALE, which confirmed that WISEJ0909+0002 is an ELIRG. A remarkably high LIR despite very low NH would indicate that we are witnessing a short-lived phase in which hydrogen gas along the line of sight is blown outward, whereas warm and hot dust heated by AGNs still exists. As a consequence of the eROSITA All-Sky Survey, 6:8+16 5:6X 102 such X-ray-bright ELIRGs are expected to be discovered in the entire extragalactic sky ( jb j > 10ffi). This can potentially be the key population to constrain the bright end of IR luminosity functions.

  27. Introducing piXedfit: A Spectral Energy Distribution Fitting Code Designed for Resolved Sources

    Abdurro’uf, Yen-Ting Lin, Po-Feng Wu, Masayuki Akiyama

    The Astrophysical Journal Supplement Series 254 (1) 15-15 2021年5月1日

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4365/abebe2  

    ISSN:0067-0049

    eISSN:1538-4365

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    We present piXedfit, pixelized spectral energy distribution (SED) fitting, a Python package that provides tools for analyzing spatially resolved properties of galaxies using multiband imaging data alone or in combination with integral field spectroscopy (IFS) data. It has six modules that can handle all tasks in the spatially resolved SED fitting. The SED-fitting module uses the Bayesian inference technique with two kinds of posterior sampling methods: Markov Chain Monte Carlo (MCMC) and random dense sampling of parameter space (RDSPS). We test the performance of the SED-fitting module using mock SEDs of simulated galaxies from IllustrisTNG. The SED fitting with both posterior sampling methods can recover physical properties and star formation histories of the IllustrisTNG galaxies well. We further test the performance of piXedfit modules by analyzing 20 galaxies observed by the CALIFA and MaNGA surveys. The data are comprised of 12-band imaging data from the Galaxy Evolution Explorer, SDSS, 2MASS, and WISE and the IFS data from CALIFA or MaNGA. The piXedfit package can spatially match (in resolution and sampling) the imaging and IFS data. By fitting only the photometric SEDs, piXedfit can predict the spectral continuum, D(n)4000, H-alpha, and H-beta well. The star formation rate derived by piXedfit is consistent with that derived from H a emission. The RDSPS method gives equally good fitting results as the MCMC and is much faster. As a versatile tool, piXedfit is equipped with a parallel computing module for efficient analysis of large data sets and will be made publicly available (https://github.com/aabdurrouf/piXedfit).

  28. Atmospheric turbulence profiling with multi-aperture scintillation of a Shack–Hartmann sensor

    Hajime Ogane, Masayuki Akiyama, Shin Oya, Yoshito Ono

    Monthly Notices of the Royal Astronomical Society 503 (4) 5778-5788 2021年4月14日

    出版者・発行元:Oxford University Press ({OUP})

    DOI: 10.1093/mnras/stab105  

    ISSN:0035-8711

    eISSN:1365-2966

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    Adaptive optics (AO) systems using tomographic estimation of three-dimensional structure of atmospheric turbulence requires vertical atmospheric turbulence profile, which describes turbulence strength as a function of altitude as a prior information. We propose a novel method to reconstruct the profile by applying Multi Aperture Scintillation Sensor (MASS) method to scintillation data obtained by a Shack-Hartmann wavefront sensor (SH-WFS). Compared to the traditional MASS, which uses atmospheric scintillation within 4 concentric annular apertures, the new method utilizes scintillation in several hundreds of spatial patterns, which are created by combinations of SH-WFS subapertures. Accuracy of the turbulence profile reconstruction is evaluated with Bayesian inference, and it is confirmed that turbulence profile with more than 10 layers can be reconstructed thanks to the large number of constraints. We demonstrate the new method with a SH-WFS attached to the 50 cm telescope at Tohoku university and confirm that general characteristics of atmospheric turbulence profile is reproduced.

  29. Black Hole and Galaxy Coevolution in Moderately Luminous Active Galactic Nuclei at z ∼ 1.4 in SXDF

    Kenta Setoguchi, Yoshihiro Ueda, Yoshiki Toba, Masayuki Akiyama

    The Astrophysical Journal 909 (2) 188-188 2021年3月1日

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/abdf55  

    ISSN:0004-637X

    eISSN:1538-4357

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    We investigate the relation of black hole mass versus host stellar mass and that of mass accretion rate versus star formation rate (SFR) in moderately luminous (log L-bol similar to 44.5 46.5 erg s(-1)), X-ray selected broad-line active galactic nuclei (AGNs) at z = 1.18-1.68 in the Subaru/XMM-Newton Deep Field. The far-infrared to far-ultraviolet spectral energy distributions of 85 AGNs are reproduced with the latest version of Code Investigating GALaxy Emission (CIGALE), where the AGN clumpy torus model SKIRTOR is implemented. Most of their hosts are confirmed to be main-sequence star-forming galaxies. We find that the mean ratio of the black hole mass (M-BH) to the total stellar mass (M-stellar) is log M-BH/M-stellar = -2.2, which is similar to the local black hole-to-bulge mass ratio. This suggests that if the host galaxies of these moderately luminous AGNs at z similar to 1.4 are dominated by bulges, they already established the local black hole mass-bulge mass relation; if they are disk dominant, their black holes are overmassive relative to the bulges. The AGN bolometric luminosities and SFR show a good correlation with ratios higher than that expected from the local black hole-to-bulge mass relation, suggesting that these AGNs are in a SMBH-growth dominant phase.

  30. SPICA Mid-infrared Instrument (SMI): The latest design and specifications

    Takehiko Wada, Hidehiro Kaneda, Takuma Kokusho, Toyoaki Suzuki, Kumiko Morihana, Takurou Tsuchikawa, Yuki Kuroda, Daichi Ishikawa, Shinki Oyabu, Naoki Isobe, Daisuke Ishihara, Hideo Matsuhara, Koichi Nagase, Takao Nakagawa, Takafumi Ootsubo, Mitsuyoshi Yamagishi, Hiroshi Maeshima, Shunsuke Onishi, Kosei Matsumoto, Satoshi Itoh, Mizuho Uchiyama, Ryan Lau, Hiromichi Ebihara, Hanae Inami, Koji Kawabata, Yasumasa Kasaba, Takeshi Sakanoi, Yoshifusa Ita, Masayuki Akiyama, Itsuki Sakon, Takafumi Kamizuka, Takashi Miyata, Kohji Tsumura, Masato Naruse, Youichi Ohyama, Shiang-Yu Wang, Hiroshi Shibai

    SPACE TELESCOPES AND INSTRUMENTATION 2020: OPTICAL, INFRARED, AND MILLIMETER WAVE 11443 2021年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2561157  

    ISSN:0277-786X

    eISSN:1996-756X

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    SMI (SPICA Mid-infrared Instrument) is one of the three focal-plane science instruments for SPICA. SMI is the Japanese-led instrument proposed and managed by a university consortium. SMI covers the wavelength range from 10 to 36 mu m with four separate channels: the low-resolution (R = 60 - 160) spectroscopy function for 17 - 36 mu m, the broad-band (R = 5) imaging function at 34 mu m, the mid-resolution (R = 1400 - 2600) spectroscopy function for 18 - 36 mu m, and the high-resolution (R = 29000) spectroscopy function for 10 - 18 mu m. In this presentation, we will show the latest design and specifications of SMI as a result of feasibility studies.

  31. Faint Quasars Live in the Same Number Density Environments as Lyman Break Galaxies at z ∼ 4

    Hisakazu Uchiyama, Masayuki Akiyama, Jun Toshikawa, Nobunari Kashikawa, Roderik Overzier, Tohru Nagao, Kohei Ichikawa, Murilo Marinello, Masatoshi Imanishi, Masayuki Tanaka, Yoshiki Matsuoka, Yutaka Komiyama, Shogo Ishikawa, Masafusa Onoue, Mariko Kubo, Yuichi Harikane, Kei Ito, Shigeru Namiki, Yongming Liang

    The Astrophysical Journal 905 (2) 2020年12月21日

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/abc47b  

    ISSN:0004-637X

    eISSN:1538-4357

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    Characterizing high-z quasar environments is key to understanding the coevolution of quasars and the surrounding galaxies. To restrict their global picture, we statistically examine the g-dropout galaxy overdensity distribution around 570 faint quasar candidates at z similar to 4, based on the Hyper Suprime-Cam Subaru Strategic Program survey. We compare the overdensity significances of g-dropout galaxies around the quasars with those around g-dropout galaxies, and find no significant difference between their distributions. A total of 4 (22) out of the 570 faint quasars, 0.7-0.4+0.8, are found to be associated with the >4 sigma overdense regions within an angular separation of 1.8 (3.0) arcmin, which is the typical size of protoclusters at this epoch. This is similar to the fraction of g-dropout galaxies associated with the >4 sigma overdense regions. This result is consistent with our previous work in which 4 sigma overdense regions within 18 and 30 separations, respectively. Therefore, we suggest that the galaxy number densities around quasars are independent of their luminosity, and most quasars do not preferentially appear in the richest protocluster regions at z similar to 4. The lack of an apparent positive correlation between the quasars and the protoclusters implies that (i) the gas-rich major merger rate is relatively low in the protocluster regions, (ii) most high-z quasars may appear through secular processes, or (iii) some dust-obscured quasars exist in the protocluster regions.

  32. NuSTAR Non-detection of a Faint Active Galactic Nucleus in an Ultraluminous Infrared Galaxy with Kpc-scale Fast Wind

    Xiaoyang Chen, Kohei Ichikawa, Hirofumi Noda, Taiki Kawamuro, Toshihiro Kawaguchi, Yoshiki Toba, Masayuki Akiyama

    The Astrophysical Journal 905 (1) 2020年12月4日

    出版者・発行元:American Astronomical Society

    DOI: 10.3847/2041-8213/abca30  

    ISSN:2041-8205

    eISSN:2041-8213

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    Large-scale outflows are generally considered to be possible evidence that active galactic nuclei (AGNs) can severely affect their host galaxies. Recently, an ultraluminous infrared galaxy (ULIRG) at z = 0.49, AKARI J0916248+073034, was found to have a galaxy-scale [O iii] lambda 5007 outflow with one of the highest energy-ejection rates at z < 1.6. However, the central AGN activity estimated from its torus mid-infrared (MIR) radiation is weak relative to the luminous [O iii] emission. In this work we report the first NuSTAR hard X-ray follow-up of this ULIRG to constrain its current AGN luminosity. The intrinsic 2-10 keV luminosity shows a 90% upper limit of 3.0 x 10(43) erg s(-1) assuming Compton-thick obscuration (N-H = 1.5 x 10(24) cm(-2)), which is only 3.6% of the luminosity expected from the extinction-corrected [O iii] luminosity. Using the NuSTAR observation, we successfully identify that this ULIRG has a very extreme case of X-ray deficit among local ULIRGs. A possible scenario to explain the drastic decline in both the corona (X-ray) and torus (MIR) is that the primary radiation from the AGN accretion disk is currently in a fading status, as a consequence of a powerful nuclear wind suggested by powerful ionized outflow in a galaxy scale.

  33. The Faint End of the Quasar Luminosity Function at z ∼ 5 from the Subaru Hyper Suprime-Cam Survey

    Mana Niida, Tohru Nagao, Hiroyuki Ikeda, Masayuki Akiyama, Yoshiki Matsuoka, Wanqiu He, Kenta Matsuoka, Yoshiki Toba, Masafusa Onoue, Masakazu A. R. Kobayashi, Yoshiaki Taniguchi, Hisanori Furusawa, Yuichi Harikane, Masatoshi Imanishi, Nobunari Kashikawa, Toshihiro Kawaguchi, Yutaka Komiyama, Hikari Shirakata, Yuichi Terashima, Yoshihiro Ueda

    The Astrophysical Journal 904 (2) 89-89 2020年11月24日

    出版者・発行元:American Astronomical Society

    DOI: 10.3847/1538-4357/abbe11  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present the quasar luminosity function at z similar to 5 derived from the optical wide-field survey data obtained as a part of the Subaru strategic program (SSP) with the Hyper Suprime-Cam (HSC). From a similar to 81.8 deg(2) area in the Wide layer of the HSC-SSP survey, we selected 224 candidates of low-luminosity quasars at z similar to 5 by adopting the Lyman-break method down to i = 24.1 mag. Based on our candidates and spectroscopically confirmed quasars from the Sloan Digital Sky Survey (SDSS), we derived the quasar luminosity function at z similar to 5, covering a wide luminosity range of -28.76 < M-1450 < -22.32 mag. We found that the quasar luminosity function is fitted by a double power-law model with a break magnitude of M-1450(*) = -25.05(-0.24)(+0.10) mag. The inferred number density of low-luminosity quasars is lower, and the derived faint-end slope, -1.22(-0.10)(+0.03), is flatter than those of previous studies at z similar to 5. A compilation of the quasar luminosity function at 4 <= z <= 6 from the HSC-SSP suggests that there is little redshift evolution in the break magnitude and in the faint-end slope within this redshift range, although previous studies suggest that the faint-end slope becomes steeper at higher redshifts. The number density of low-luminosity quasars decreases more rapidly from z similar to 5 to z similar to 6 than from z similar to 4 to z similar to 5.

  34. Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). IX. Identification of two red quasars at z > 5.6

    Nanako Kato, Yoshiki Matsuoka, Masafusa Onoue, Shuhei Koyama, Yoshiki Toba, Masayuki Akiyama, Seiji Fujimoto, Masatoshi Imanishi, Kazushi Iwasawa, Takuma Izumi, Nobunari Kashikawa, Toshihiro Kawaguchi, Chien-Hsiu Lee, Takeo Minezaki, Tohru Nagao, Akatoki Noboriguchi, Michael A. Strauss

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 72 (5) 2020年10月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psaa074  

    ISSN:0004-6264

    eISSN:2053-051X

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    We present the first discovery of dust-reddened quasars (red quasars) in the high-z universe (z > 5.6). This is a result from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, which is based on the sensitive multi-band optical imaging data produced by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. We identified four red quasar candidates from the 93 spectroscopically confirmed high-z quasars in the SHELLQs sample, based on detections in the Wide-field Infrared Survey Explorer (WISE) data at 3.4 and 4.6 mu m (rest-frame similar to 5000-6500 angstrom). The amount of dust reddening was estimated with spectral energy distribution (SED) fits over optical and mid-infrared wavelengths. Two of the four candidates were found to be red quasars with dust reddening of E(B - V) > 0.1. The remaining SHELLQs quasars without individual WISE detections are significantly fainter in the WISE bands and bluer than the red quasars, although we did detect them in the W1 band in a stacked image. We also conducted the same SED fits for high-z optically-luminous quasars, but no red quasar was found. This demonstrates the power of Subaru HSC to discover high-z red quasars, which are fainter than the limiting magnitudes of past surveys in the rest-frame ultraviolet, due to dust extinction.

  35. Tracing the Coevolution Path of Supermassive Black Holes and Spheroids with AKARI-selected Ultraluminous IR Galaxies at Intermediate Redshifts

    Xiaoyang Chen, Masayuki Akiyama, Kohei Ichikawa, Hirofumi Noda, Yoshiki Toba, Issei Yamamura, Toshihiro Kawaguchi, U. F. Abdurro', Mitsuru Kokubo

    ASTROPHYSICAL JOURNAL 900 (1) 51-51 2020年9月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/aba599  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present the stellar population and ionized-gas outflow properties of ultraluminous IR galaxies (ULIRGs) at z = 0.1-1.0 that are selected from the AKARI far-IR all-sky survey. We construct a catalog of 1077 ULIRGs to examine feedback effects after major mergers. Of the 1077 ULIRGs, 202 are spectroscopically identified by SDSS and Subaru/FOCAS observations. Thanks to the deeper depth and higher resolution of AKARI compared to the previous Infrared Astronomical Satellite (IRAS) survey and reliable identification from the Wide-field Infrared Survey Explorer (WISE) mid-IR pointing, the sample is unique in identifying optically faint (i similar to 20) IR-bright galaxies, which could be missed in previous surveys. A self-consistent spectrum and broadband spectral energy distribution (SED) decomposition method, which constrains stellar population properties in SED modeling based on spectral fitting results, has been employed for 149 ULIRGs whose optical continua are dominated by host galaxies. They are massive galaxies (M-star similar to 10(11)-10(12)M(circle dot)) associated with intense star formation activities (SFR similar to 200-2000 M-circle dot yr(-1)). The sample covers a range of active galactic nucleus (AGN) bolometric luminosity of 10(10)-10(13) L-circle dot, and the outflow velocity measured from the [OIII] 5007 angstrom line shows a correlation with AGN luminosity. Eight galaxies show extremely fast outflows with velocity up to 1500-2000 km s(-1). However, the coexistence of vigorous starbursts and strong outflows suggests the star formation has not been quenched during the ULIRG phase. By deriving the stellar mass and mass fraction of the young stellar population, we find no significant discrepancies between stellar properties of ULIRGs with weak and powerful AGNs. The results are not consistent with the merger-induced evolutionary scenario, which predicts that star formation-dominated ULIRGs will show smaller stellar masses and younger stellar populations compared to AGN-dominated ULIRGs.

  36. Properties of the environment around active galactic nucleus / luminous galaxy pairs through the HSC wide survey

    Yuji Shirasaki, Masayuki Akiyama, Yoshiki Toba, Wanqiu He, Tomotsugu Goto

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 72 (4) 2020年8月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psaa037  

    ISSN:0004-6264

    eISSN:2053-051X

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    We investigated the properties of active galactic nucleus (AGN) environments, particularly environments where the association of a luminous galaxy (LG) is found within 4 Mpc from an AGN with redshift 0.8-1.1. For comparison, three additional AGN environments, (namely, AGNs of all types, type 1 AGNs with X-ray and/or radio detection, and type 2 AGNs) and an environment of blue M-*,the characteristic luminosity of the Schechter function, galaxies were investigated. The cross-correlation function with the surrounding galaxies was measured and compared between the AGN and blue galaxy samples. We also compared the distributions of color, absolute magnitude, and stellar mass of the galaxies around such target objects. The properties of clusters detected using surrounding galaxies selected based on a photometric redshift were examined and compared for different samples. The target AGNs were drawn from the Million Quasars (MILLIQUAS) catalog, and the blue galaxies were drawn from six redshift survey catalogs (SDSS, WiggleZ, DEEP2, VVDS, VIPERS, and PRIMUS). The galaxies used as a measure of the environment around the targets were drawn from the 518a internal data released by the Hyper Suprime-Cam Subaru Strategic Program. We found that, among the five AGN and blue galaxy samples considered, the environment of AGN-LG pairs is the most enriched with luminous galaxies. We also found an enhancement in the number of mass-selected clusters in the AGN-LG pair sample against those in the other samples. The results obtained in this study indicate that existence of multiple clusters is the major driver in the association of AGNs and LGs, rather than a single large-mass dark matter halo hosting the AGN.

  37. A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). III. Discovery of a z=4.72 Radio Galaxy with the Lyman Break Technique

    Takuji Yamashita, Tohru Nagao, Hiroyuki Ikeda, Yoshiki Toba, Masaru Kajisawa, Yoshiaki Ono, Masayuki Tanaka, Masayuki Akiyama, Yuichi Harikane, Kohei Ichikawa, Toshihiro Kawaguchi, Taiki Kawamuro, Kotaro Kohno, Chien-Hsiu Lee, Kianhong Lee, Yoshiki Matsuoka, Mana Niida, Kazuyuki Ogura, Masafusa Onoue, Hisakazu Uchiyama

    ASTRONOMICAL JOURNAL 160 (2) 60-60 2020年8月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-3881/ab98fe  

    ISSN:0004-6256

    eISSN:1538-3881

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    We report a discovery of a z = 4.72 radio galaxy, HSC J083913.17+011308.1, using the Lyman break technique with the Hyper Suprime-Cam Subaru Strategic Survey (HSC-SSP) catalog for Very Large Array Faint Images of the Radio Sky at Twenty centimeter radio sources. The number of known high-z radio galaxies (HzRGs) at z > 3 is quite small to constrain the evolution of HzRGs so far. The deep and wide-area optical survey by HSC-SSP enables us to apply the Lyman break technique to a large search for HzRGs. For an HzRG candidate among pre-selected r-band dropouts with a radio detection, a follow-up optical spectroscopy with the Gemini Multi-Object Spectrographs (GMOS)/Gemini has been performed. The obtained spectrum presents a clear Ly alpha emission line redshifted to z = 4.72. The spectral energy distribution fitting analysis with the rest-frame UV and optical photometries suggests the massive nature of this HzRG with logM*/M-circle dot = 11.4. The small equivalent width of Ly alpha and the moderately red UV colors indicate its dusty host galaxy, implying a chemically evolved and dusty system. The radio spectral index does not meet a criterion for an ultra-steep spectrum, alpha(325)(1400) of -1.1 and alpha(150)(1400) of -0.9, demonstrating that the HSC-SSP survey compensates for a subpopulation of HzRGs that are missed in surveys focusing on an ultra-steep spectral index.

  38. ULTIMATE-Subaru: System Performance Modeling of GLAO and Wide-Field NIR instruments

    Yosuke Minowa, Yusei Koyama, Kenshi Yanagisawa, Kentaro Motohara, Ichi Tanaka, Yoshito Ono, Takashi Hattori, Clergeon Christophe, Yutaka Hayano, Masayuki Akiyama, Tadayuki Kodama, Celine D'Orgeville, Francois Rigaut, Shiang-Yu Wang, Michitoshi Yoshida

    MODELING, SYSTEMS ENGINEERING, AND PROJECT MANAGEMENT FOR ASTRONOMY IX 11450 2020年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2561950  

    ISSN:0277-786X

    eISSN:1996-756X

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    ULTIMATE-Subaru is a next large facility instrument project at Subaru telescope. We will develop a 14x14 sq. arcmin wide-field near-infrared (NIR) imager and a multi-object spectrograph with the aid of a ground-layer adaptive optics system (GLAO), which will uniformly improve the seeing by a factor of 2 over a wide field of view up to similar to 20 arcmin in diameter. We have developed system modeling of the GLAO and wide-field NIR instruments to define the system level requirements flow down from science cases and derive the system performance budgets based on the GLAO end-to-end numerical simulation and optical system models of the telescope and wide-field NIR science instruments. In this paper, we describe the system performance modeling of ULTIMATE-Subaru and present an overview of the requirements flow down.

  39. ULTIMATE-Subaru: Enhancing the Subaru's wide-field capability with GLAO

    Yosuke Minowa, Yusei Koyama, Yoshito H. Ono, Ichi Tanaka, Takashi Hattori, Christophe S. Clergeon, Masayuki Akiyama, Tadayuki Kodama, Kentaro Motohara, Francois Rigaut, Celine d'Orgeville, Shiang-Yu Wang, Michitoshi Yoshida

    ADVANCES IN OPTICAL ASTRONOMICAL INSTRUMENTATION 2019 11203 2020年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2560539  

    ISSN:0277-786X

    eISSN:1996-756X

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    ULTIMATE-Subaru is a next large facility instrument project at Subaru telescope. We will develop a 14x14 arcmin(2) wide-field near-infrared (1.0-2.5 mu m) imager and a multi-object spectrograph with the aid of a groundlayer adaptive optics system (GLAO), which will uniformly improve the seeing by a factor of 2 over a wide field of view up to similar to 20 arcmin in diameter. The expected spatial resolution by the GLAO correction is about 0.2 arcsec FWHM in K-band under moderate seeing conditions at Subaru telescope. ULTIMATE-Subaru will provide a unique capability to realize wide-field and high spatial resolution survey observations in near infrared in the era of TMT. In this paper, we introduce the project overview including the GLAO and near-infrared instrument conceptual design. We also describe the future wide-field strategy at Subaru telescope with ULTIMATE-Subaru together with HSC and PFS.

  40. Flavor Compounds Affecting the Sensory Characteristics of a Lactobacillus-fermented Dairy Beverage during Two Weeks of Refrigerated Storage

    Taisuke Suzuki, Masayuki Akiyama, Yoshiyasu Sato, Misako Okaue, Yusuke Murakami, Masanobu Onishi, Yasumichi Mizota, Hiroshi Ochi, Reiko Koizumi, Kazuhiro Miyaji, Michio Ikeda, Hisakatsu Iwabuchi

    FOOD SCIENCE AND TECHNOLOGY RESEARCH 26 (1) 139-152 2020年1月

    出版者・発行元:JAPANESE SOC FOOD SCI & TECHNOLOGY

    DOI: 10.3136/fstr.26.139  

    ISSN:1344-6606

    eISSN:1881-3984

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    Lactobacillus paracasei MCC1849 (LP) has the potential to modulate immune function. The purpose of this study was to investigate the impact of flavor compounds on changes in sensory characteristics during refrigerated storage of a functional LP-fermented dairy beverage. A sample containing 1 x 10(8) cells/mL viable LP stored at 10 degrees C for 0, 1, or 2 weeks was evaluated by a trained panel. The scores for 'odor', 'afterflavor of fermented odor', 'fermented odor', and 'acidity' increased significantly. Three types of gas chromatography-mass spectrometry for volatiles in the solvent extract and headspace gas, and also for hydrophilic compounds were performed. The compounds related to the change in four sensory attributes were examined by partial least squares regression analysis. A non-stored sample with a flavor composed of 13 compounds related to the attributes replicated the fermented odor characteristics of the 2-weeks-stored sample.

  41. Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). X. Discovery of 35 Quasars and Luminous Galaxies at 5.7 <= z <= 7.0 査読有り

    Yoshiki Matsuoka, Kazushi Iwasawa, Masafusa Onoue, Nobunari Kashikawa, Michael A. Strauss, Chien-Hsiu Lee, Masatoshi Imanishi, Tohru Nagao, Masayuki Akiyama, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Takuma Izumi, Toshihiro Kawaguchi, Nanako Kato, Satoshi Kikuta, Kotaro Kohno, Yutaka Komiyama, Shuhei Koyama, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Mana Niida, Atsushi J. Nishizawa, Akatoki Noboriguchi, Masamune Oguri, Yoshiaki Ono, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Andreas Schulze, John D. Silverman, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Tadafumi Takata, Masayuki Tanaka, Ji-Jia Tang, Yoshiki Toba, Yousuke Utsumi, Shiang-Yu Wang, Takuji Yamashita

    ASTROPHYSICAL JOURNAL 883 (2) 183-183 2019年10月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/ab3c60  

    ISSN:0004-637X

    eISSN:1538-4357

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    We report the discovery of 28 quasars and 7 luminous galaxies at 5.7 <= z <= 7.0. This is the tenth in a series of papers from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, which exploits the deep multiband imaging data produced by the Hyper Suprime-Cam ( HSC) Subaru Strategic Program survey. The total number of spectroscopically identified objects in SHELLQs has now grown to 93 high-z quasars, 31 high-z luminous galaxies, 16 [O III] emitters at z similar to 0.8, and 65 Galactic cool dwarfs (low- mass stars and brown dwarfs). These objects were found over 900 deg2, surveyed by HSC between 2014 March and 2018 January. The full quasar sample includes 18 objects with very strong and narrow Lya emission, whose stacked spectrum is clearly different from that of other quasars or galaxies. While the stacked spectrum shows N V.1240 emission and resembles that of lower-z narrow-line quasars, the small Lya width may suggest a significant contribution from the host galaxies. Thus, these objects may be composites of quasars and star-forming galaxies.

  42. An Observational Link between AGN Eddington Ratio and [N II]lambda 6583/H alpha at 0.6 < z < 1.7

    Kyuseok Oh, Yoshihiro Ueda, Masayuki Akiyama, Hyewon Suh, Michael J. Koss, Daichi Kashino, Gunther Hasinger

    ASTROPHYSICAL JOURNAL 880 (2) 112-112 2019年8月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/ab288b  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present an observed relationship between the Eddington ratio (lambda(Edd)) and the optical narrow-emission-line ratio ([N II]lambda 6583/H alpha) of X-ray-selected broad-line active galactic nuclei (AGNs) at 0.6 < z < 1.7. We use 27 near-infrared spectra from the Fiber Multi-Object Spectrograph along with 26 sources from the literature. We show that the lambda(Edd) and [N II]lambda 6583/H alpha ratio at 0.6 < z < 1.7 exhibits a similar anti-correlation distribution of lambda(Edd)-[N II]lambda 6583/H alpha, as has been found for local (< z > = 0.036), ultra-hard, X-ray-selected AGNs. The observed distribution implies that there is a consistent relationship from local to z similar to 1.7, which corresponds from the present time to 4 Gyr old. Further study of high-redshift, low-Eddington-ratio AGNs (log lambda(Edd) < -2) is necessary to determine fully whether the lambda(Edd)-[N II]lambda 6583/H alpha anti-correlation still holds in high-redshift AGNs at low Eddington ratios.

  43. A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). II. Physical Properties Derived from the SED Fitting with Optical, Infrared, and Radio Data 査読有り

    Yoshiki Toba, Takuji Yamashita, Tohru Nagao, Wei-Hao Wang, Yoshihiro Ueda, Kohei Ichikawa, Toshihiro Kawaguchi, Masayuki Akiyama, Bau-Ching Hsieh, Masaru Kajisawa, Chien-Hsiu Lee, Yoshiki Matsuoka, Akatoki Noboriguchi, Masafusa Onoue, Malte Schramm, Masayuki Tanaka, Yutaka Komiyama

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 243 (1) 15-15 2019年7月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4365/ab238d  

    ISSN:0067-0049

    eISSN:1538-4365

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    We present physical properties of radio galaxies (RGs) with f(1.4) GHz > 1 mJy discovered by Subaru Hyper Suprime-Cam (HSC) and Very Large Array Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. For 1056 FIRST RGs at 0 < z <= 1.7 with HSC counterparts in about 100 deg(2), we compiled multi-wavelength data of optical, near-infrared (IR), mid-IR, far-IR, and radio (150 MHz). We derived their color excess (E(B - V)(*)), stellar mass, star formation rate (SFR), IR luminosity, the ratio of IR and radio luminosity (q(IR)), and radio spectral index (alpha(radio)) that are derived from the spectral energy distribution (SED) fitting with CIGALE. We also estimated Eddington ratio based on stellar mass and integration of the best-fit SEDs of active galactic nucleus (AGN) component. We found that E(B - V)(*), SFR, and IR luminosity clearly depend on redshift while stellar mass, q(IR), and alpha(radio) do not significantly depend on redshift. Since optically faint (i(AB) >= 21.3) RGs that are newly discovered by our RG survey tend to be high redshift, they tend to not only have a large dust extinction and low stellar mass but also have high SFR and AGN luminosity, high IR luminosity, and high Eddington ratio compared with optically bright ones. The physical properties of a fraction of RGs in our sample seem to differ from a classical view of RGs with massive stellar mass, low SFR, and low Eddington ratio, demonstrating that our RG survey with HSC and FIRST provides us curious RGs among entire RG population.

  44. Discovery of a strong ionized-gas outflow in an AKARI-selected ultra-luminous infrared galaxy at z=0.5 査読有り

    Xiaoyang Chen, Masayuki Akiyama, Hirofumi Noda, Abdurro'uf, Yoshiki Toba, Issei Yamamura, Toshihiro Kawaguchi, Mitsuru Kokubo, Kohei Ichikawa

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 71 (2) 2019年4月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psz002  

    ISSN:0004-6264

    eISSN:2053-051X

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    In order to construct a sample of ultra-luminous infrared galaxies (ULIRGs; with infrared luminosity L-IR > 10(12) L-circle dot) at 0.5 < z < 1, we are conducting an optical follow-up program for bright 90 mu m far-infrared sources with a faint optical (i < 20 mag) counterpart selected in the AKARI Far-Infrared Surveyor (FIS) Bright Source catalog (Ver.2). AKARI-FIS-V2 J0916248+073034, identified as a ULIRG at z = 0.49 in the spectroscopic follow-up observation, indicates signatures of an extremely strong outflow in its emission line profiles. Its [O III] 5007 angstrom emission line shows a full width at half-maximum (FWHM) of 1830 kms(-1) and velocity shift of -770 kms(-1) relative to the stellar absorption lines. Furthermore, the low-ionization [OII] 3726 angstrom 3729 angstrom doublet also shows a large FWHM of 910 kms(-1) and velocity shift of -380 kms(-1). After the removal of an unresolved nuclear component, the long-slit spectroscopy 2D image possibly shows that the outflow extends to a radius of 4 kpc. The mass outflow and energy ejection rates are estimated to be 500M(circle dot) yr(-1) and 4 x 10(44) erg s(-1), respectively, which imply that the outflow is among the most powerful ones observed in ULIRGs and quasi-stellar objects at 0.3 < z < 1.6. The co-existence of the strong outflow and intense star formation (star formation rate of 990 M-circle dot yr(-1)) indicates that the feedback of the strong outflow has not severely affected the star-forming region of the galaxy.

  45. Discovery of the First Low-luminosity Quasar at z > 7 査読有り

    Yoshiki Matsuoka, Masafusa Onoue, Nobunari Kashikawa, Michael A. Strauss, Kazushi Iwasawa, Chien-Hsiu Lee, Masatoshi Imanishi, Tohru Nagao, Masayuki Akiyama, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Takuma Izumi, Toshihiro Kawaguchi, Nanako Kato, Satoshi Kikuta, Kotaro Kohno, Yutaka Komiyama, Shuhei Koyama, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Mana Niida, Atsushi J. Nishizawa, Akatoki Noboriguchi, Masamune Oguri, Yoshiaki Ono, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Andreas Schulze, Hikari Shirakata, John D. Silverman, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Tadafumi Takata, Masayuki Tanaka, Ji-Jia Tang, Yoshiki Toba, Yousuke Utsumi, Shiang-Yu Wang, Takuji Yamashita

    ASTROPHYSICAL JOURNAL LETTERS 872 (1) L2 2019年2月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/2041-8213/ab0216  

    ISSN:2041-8205

    eISSN:2041-8213

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    We report the discovery of a quasar at z = 7.07, which was selected from the deep multi-band imaging data collected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. This quasar, HSC J124353.93 +010038.5, has an order of magnitude lower luminosity than do the other known quasars at z > 7. The rest-frame ultraviolet absolute magnitude is M-1450 = -24.13 +/- 0.08 mag and the bolometric luminosity is L-bol = (1.4 +/- 0.1) x 10(46) erg s(-1). Its spectrum in the optical to near-infrared shows strong emission lines, and shows evidence for a fast gas outflow, as the C IV line is blueshifted and there is indication of broad absorption lines. The Mg IT-based black hole mass is M-BH = (3.3 +/- 2.0) x 10(8) M-circle dot, thus indicating a moderate mass accretion rate with an Eddington ratio) lambda(Edd) = 0.34 0.20. It is the first z > 7 quasar with sub-Eddington accretion, besides being the third most distant quasar known to date. The luminosity and black hole mass are comparable to, or even lower than, those measured for the majority of low-z quasars discovered by the Sloan Digital Sky Survey, and thus this quasar likely represents a z > 7 counterpart to quasars commonly observed in the low-z universe.

  46. Enhancement of H I absorption associated with the z = 3.1 large-scale proto-cluster and characteristic structures with AGNs sculptured over Gpc scale in the SSA22 field 査読有り

    Hayashino} T, Inoue} A.~K, Kousai} K, Kashikawa} N, Mawatari} K, Matsuda} Y, Tejos} N, Prochaska} J, Iwata} I, Noll} S, Burgarella} D, Yamada} T, Akiyama} M

    \mnras 484 (4) 5868-5887 2019年

    出版者・発行元:None

    DOI: 10.1093/mnras/stz388  

    ISSN:0035-8711

    eISSN:1365-2966

  47. A Catastrophic Failure to Build a Massive Galaxy around a Supermassive Black Hole at z=3.84 査読有り

    Malte Schramm, Wiphu Rujopakarn, John, D. Silverman, Tohru Nagao, Andreas Schulze, Masayuki Akiyama, Hiroyuki Ikeda, Kohji Ohta, Jari Kotilainen

    The Astrophysical Journal 881 (2) 145-145 2019年

    出版者・発行元:None

    DOI: 10.3847/1538-4357/ab2cd3  

    eISSN:1538-4357

  48. Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). V. Quasar Luminosity Function and Contribution to Cosmic Reionization at z=6 査読有り

    Yoshiki Matsuoka, Michael A. Strauss, Nobunari Kashikawa, Masafusa Onoue, Kazushi Iwasawa, Ji-Jia Tang, Chien-Hsiu Lee, Masatoshi Imanishi, Tohru Nagao, Masayuki Akiyama, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Takuma Izumi, Toshihiro Kawaguchi, Nanako Kato, Satoshi Kikuta, Kotaro Kohno, Yutaka Komiyama, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Mana Niida, Atsushi J. Nishizawa, Akatoki Noboriguchi, Masamune Oguri, Yoshiaki Ono, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Andreas Schulze, Hikari Shirakata, John D. Silverman, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Tadafumi Takata, Masayuki Tanaka, Yoshiki Toba, Yousuke Utsumi, Shiang-Yu Wang, Takuji Yamashita

    ASTROPHYSICAL JOURNAL 869 (2) 150-150 2018年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/aaee7a  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present new measurements of the quasar luminosity function (LF) at z similar to 6 over an unprecedentedly wide range of the rest-frame ultraviolet luminosity M-1450 from -30 to -22 mag. This is the fifth in a series of publications from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, which exploits the deep multiband imaging data produced by the Hyper Suprime-Cam Subaru Strategic Program survey. The LF was calculated with a complete sample of 110 quasars at 5.7 <= z <= 6.5, which includes 48 SHELLQs quasars discovered over 650 deg(2) and 63 brighter quasars discovered by the Sloan Digital Sky Survey and the Canada-France-Hawaii Quasar Survey (including one overlapping object). This is the largest sample of z similar to 6 quasars with a well-defined selection function constructed to date, which has allowed us to detect significant flattening of the LF at its faint end. A double power-law function fit to the sample yields a faint-end slope alpha = -1.23(-0.34)(+0.44), a bright-end slope beta = -2.73(-0.31)(+0.23), a break magnitude M*(1450) = -24.90(-0.90)(+0.75), and a characteristic space density Phi* = 10.9(-6.8)(+10.0) Gpc(-3) mag(-1). Integrating this best-fit model over the range -18 < M-1450 < -30 mag, quasars emit ionizing photons at the rate of <(n)over dot>(ion) = 10(48.8 +/- 0.1) s(-1) Mpc(-3) at z = 6.0. This is less than 10% of the critical rate necessary to keep the intergalactic medium ionized, which indicates that quasars are not a major contributor to cosmic reionization.

  49. An FMOS Survey of Moderate- luminosity, Broad-line AGNs in COSMOS, SXDS, and E-CDF-S 査読有り

    Andreas Schulze, John D. Silverman, Daichi Kashino, Masayuki Akiyama, Malte Schramm, Dave Sanders, Jeyhan Kartaltepe, Emanuele Daddi, Giulia Rodighiero, Alvio Renzini, Nobuo Arimoto, Tohru Nagao, Annagrazia Puglisi, Benny Trakhtenbrot, Francesca Civano, Hyewon Suh

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 239 (2) 22-22 2018年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4365/aae82f  

    ISSN:0067-0049

    eISSN:1538-4365

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    We present near-IR spectroscopy in the J- and H-bands for a large sample of 243 X-ray-selected, moderate-luminosity Type 1 active galactic nuclei (AGNs) in the COSMOS, SXDS, and E-CDF-S survey fields using the multi-object spectrograph Subaru/FMOS. Our sample covers the redshift range 0.5 less than or similar to z less than or similar to 3.0 and X-ray luminosity range of 10(43) less than or similar to L[2-10keV] less than or similar to 10(45) erg s(-1). We provide emission-line properties and derived virial black hole mass estimates, bolometric luminosities, and Eddington ratios, based on H alpha (211), H beta (63), and Mg II (4). We compare line widths, luminosities, and black hole mass estimates from H alpha and H beta, and augment these with commensurate measurements of Mg II and C IV detected in optical spectra. We demonstrate the robustness of using H alpha, H beta, and Mg II as reliable black hole mass estimators for high-z moderate-luminosity AGNs, while the use of C IV is prone to large uncertainties (greater than or similar to 0.4 dex). We extend a recently proposed correction based on the C IV blueshift to lower luminosities and black hole masses. While our sample shows an improvement in their C IV black hole mass estimates, the deficit of high blueshift sources reduces its overall importance for moderate-luminosity AGNs compared to the most luminous quasars. In addition, we revisit luminosity correlations between L-bol, L[2-10keV], L-[O III], L-5100, and L-H alpha and find them to be consistent with a simple empirical model, based on a small number of well-established scaling relations. Finally, we highlight our highest redshift AGN, CID 781, at z = 4.6, which has the lowest black hole mass (similar to 10(8) M-circle dot) among current near-IR samples at this redshift and is in a state of fast growth.

  50. Changes in Odor Compounds of a Lactobacillus-fermented Dairy Beverage during Two Weeks of Refrigerated Storage

    Masayuki Akiyama, Taisuke Suzuki, Yusuke Murakami, Masanobu Onishi, Yasumichi Mizota, Kazuhiro Miyaji, Michio Ikeda, Hisakatsu Iwabuchi

    FOOD SCIENCE AND TECHNOLOGY RESEARCH 24 (6) 1129-1137 2018年11月

    出版者・発行元:KARGER

    DOI: 10.3136/fstr.24.1129  

    ISSN:1344-6606

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    Lactobacillus paracasei MCC1849 (LP) has the potential to modulate immune function. To develop a functional LP-fermented dairy beverage, changes in intensities of odorants during two weeks of refrigerated storage were investigated by gas chromatography-olfactometry (GC-O, CharmAnalysis (TM)). A fermented dairy beverage containing 1 x 10(8) viable LP cells/mL, 0.8 % non-fat milk solids, and 0.1 % milk fat was prepared, and then stored at 10 degrees C for 0, 1, or 2 weeks before solvent extraction. GC-O of the volatiles in the resulting extracts detected 34 odorants, of which 29 were identified. Among the identified compounds, 4-(4'-hydroxyphenyl)-2-butanone (raspberry ketone) was also detected by GC-mass spectrometry, representing the first identification of this compound as an odorant in fermented dairy products to our knowledge. Principal component analysis of the GC-O data permitted discrimination among the 3 stored samples according to duration of storage, and clarified the major odors contributing to the change in odor characteristics during storage.

  51. A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). I. The Optical Counterparts of FIRST Radio Sources 査読有り

    Takuji Yamashita, Tohru Nagao, Masayuki Akiyama, Wanqiu He, Hiroyuki Ikeda, Masayuki Tanaka, Mana Niida, Masaru Kajisawa, Yoshiki Matsuoka, Kodai Nobuhara, Chien-Hsiu Lee, Tomoki Morokuma, Yoshiki Toba, Toshihiro Kawaguchi, Akatoki Noboriguchi

    ASTROPHYSICAL JOURNAL 866 (2) 140-140 2018年10月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/aae1ac  

    ISSN:0004-637X

    eISSN:1538-4357

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    We report the result of optical identifications of FIRST radio sources with the Hyper Suprime-Cam Subaru Strategic Program survey (HSC-SSP). The positional cross-match within 1 '' between the FIRST and HSC-SSP catalogs (i less than or similar to 26) produced more than 3600 optical counterparts in the 156 deg(2) of the HSC-SSP field. The matched counterparts account for more than 50% of the FIRST sources in the search field, which substantially exceed previously reported fractions of SDSS counterparts (i less than or similar to 22) of -30%. Among the matched sample, 9% are optically unresolved sources such as radio-loud quasars. The optically faint (i > 21) radio galaxies (RGs) show that the fitting linear function of the 1.4 GHz source counts has a slope that is flatter than that of the bright RGs, while optically faint radio quasars show a slope steeper than that of bright radio quasars. The optically faint RGs show a flat slope in the i-band number counts down to 24 mag, implying either less massive or distant radio-active galactic nuclei (AGNs) beyond 24 mag. The photometric redshift and the comparison of colors with the galaxy models show that most of the matched RGs are distributed at redshifts from 0 to 1.5. The optically faint sample includes the high radio-loudness sources that are not seen in the optically bright sample. Such sources are located at redshift z > 1. This study gives similar to 1500 radio AGNs lying at the optically faint end and high-redshift regime not probed by previous searches.

  52. Evolution of spatially resolved star formation main sequence and surface density profiles in massive disc galaxies at 0 ≲ z ≲ 1: inside-out stellar mass buildup and quenching 査読有り

    Abdurro'uf, Akiyama, Masayuki

    Monthly Notices of the Royal Astronomical Society 479 (4) 5083-5100 2018年10月

    出版者・発行元:None

    DOI: 10.1093/mnras/sty1771  

    ISSN:0035-8711

    eISSN:1365-2966

  53. Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). IV. Discovery of 41 Quasars and Luminous Galaxies at 5.7 ≤ z ≤ 6.9 査読有り

    Matsuoka, Yoshiki, Iwasawa, Kazushi, Onoue, Masafusa, Kashikawa, Nobunari, Strauss, Michael A, Lee, Chien-Hsiu, Imanishi, Masatoshi, Nagao, Tohru, Akiyama, Masayuki, t, al. e

    The Astrophysical Journal Supplement Series 237 (1) 5-5 2018年7月

    出版者・発行元:None

    DOI: 10.3847/1538-4365/aac724  

    ISSN:0067-0049

    eISSN:1538-4365

  54. Haleakala telescopes: ハレアカラ望遠鏡と将来PLANETS望遠鏡による惑星大気・系外惑星研究の新展開

    坂野井 健, 鍵谷将人, 中川広務, 小原隆博, 笠羽康正, 平原靖大, 山田学, 岡野章一, 秋山正幸, Jeff Kuhn, Svetalana Berdyugina, Marcelo Emiliob, Gill Moretto

    Proceedings of Symposium on Planetary Science 2018 2018年

  55. Gemini Infrared Multi-Object Spectrograph: Instrument Overview

    Suresh Sivanandam, Scott Chapman, Luc Simard, Paul Hickson, Kim Venn, Simon Thibault, Marcin Sawicki, Adam Muzzin, Darren Erickson, Roberto Abraham, Masayuki Akiyama, David Andersen, Colin Bradley, Raymond Carlberg, Shaojie Chen, Carlos Correia, Tim Davidge, Sara Ellison, Kamal El-Sankary, Gregory Fahlman, Masen Lamb, Olivier Lardiere, Marie Lemoine-Busserolle, Dae-Sik Moon, Norman Murray, Alison Peck, Cyrus Shafai, Gaetano Sivo, Jean-Pierre Veran, Howard Yee

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VII 10702 107021J 2018年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2313924  

    ISSN:0277-786X

    eISSN:1996-756X

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    The Gemini Infrared Multi-Object Spectrograph (GIRMOS) is a powerful new instrument being built to facility class standards for the Gemini telescope. It takes advantage of the latest developments in adaptive optics and integral field spectrographs. GIRMOS will carry out simultaneous high-angular-resolution, spatially-resolved infrared (1 - 2.4 mu m) spectroscopy of four objects within a two-arcminute field-of-regard by taking advantage of multi-object adaptive optics. This capability does not currently exist anywhere in the world and therefore offers significant scientific gains over a very broad range of topics in astronomical research. For example, current programs for high redshift galaxies are pushing the limits of what is possible with infrared spectroscopy at 8 10 meter class facilities by requiring up to several nights of observing time per target. Therefore, the observation of multiple objects simultaneously with adaptive optics is absolutely necessary to make effective use of telescope time and obtain statistically significant samples for high redshift science. With an expected commissioning date of 2023, GIRMOS's capabilities will also make it a key followup instrument for the James Webb Space Telescope when it is launched in 2021, as well as a true scientific and technical pathfinder for future Thirty Meter Telescope (TMT) multi-object spectroscopic instrumentation. In this paper, we will present an overview of this instrument's capabilities and overall architecture. We also highlight how this instrument lays the ground work for a future TMT early-light instrument.

  56. On-going and future AO activities on Subaru Telescope

    Yoshito H. Ono, Yosuke Minowa, Christophe S. Clergeon, Etsuko Mieda, Olivier Guyon, Julien Lozi, Masayuki Akiyama, Francois Rigaut, Yutaka Hayano, Shin Oya

    ADAPTIVE OPTICS SYSTEMS VI 10703 107030M 2018年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2312379  

    ISSN:0277-786X

    eISSN:1996-756X

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    This paper presents the overview of on-going and future adaptive optics (AO) activities at the Subaru telescope on the top of Maunakea in Hawaii. Currently, two AO systems are running at the Subaru telescope: AO188, a facility single-conjugate AO system with a bimorph deformable mirror and a curvature wavefront sensor with 188 elements, and SCExAO, an additional extreme AO system operating behind AO188 and specialized for exoplanet sciences. We recently started AO188 upgrade project to improve its performance for the next 5{10 years, which will also help improving SCExAO performance. These upgrades are in line with a development for the ULTIMATE-Subaru ground layer AO system.

  57. A conceptual design study for Subaru ULTIMATE GLAO

    Francois Rigaut, Yosuke Minowa, Masayuki Akiyama, Yoshito Ono, Visa Korkiakoski, Nick Herrald, Gaston Gausachs, Christophe Clergeon, Shiang-Yu Wang, Celine d'Orgeville, Jordan Davies, Yusei Koyama, Ikuru Iwata, Tadayuki Kodama, Kentaro Motohara, Yutaka Hayano, Ichi Tanaka, Takashi Hattori, Michitoshi Yoshida

    ADAPTIVE OPTICS SYSTEMS VI 10703 1070324 2018年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2314085  

    ISSN:0277-786X

    eISSN:1996-756X

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    We report on the conceptual design study done for the Ground Layer Adaptive Optics system of the ULTIMATE-Subaru project. This is an ambitious instrument project, providing GLAO correction in a square field of view of 14 arcmin on a side, aiming to deliver improved seeing at the near infrared wavelength. Its client instruments are an imager and multi-IFU spectrograph at Cassegrain and a Multi-Object spectrograph at Nasmyth. In this paper, we introduce the ULTIMATE-Subaru project overview and its science case and report the results of the GLAO performance prediction based on the numerical simulation and conceptual design of the wavefront sensor system.

  58. Current status of the Laser Guide Star Upgrade at Subaru Telescope

    Etsuko Mieda, Yoko Tanaka, Matthew Wung, Yosuke Minowa, Christophe Clergeon, Yoshito Ono, Takashi Hattori, Yutaka Hayano, Masayuki Akiyama, Francois Rigaut, Celine d'Orgeville

    ADAPTIVE OPTICS SYSTEMS VI 10703 107033 2018年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2314093  

    ISSN:0277-786X

    eISSN:1996-756X

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    We report the current status of the laser guide star upgrade at Subaru Telescope with a new, more powerful TOPTICA/MPBC laser. While we recycle many of our existing components, such as laser launch telescope, we need to design a new mirror-based laser relay system to replace the current fiber-based relay to accommodate the high power beam. The laser unit has been delivered to Subaru office in March 2018 and installed in a testing lab in June 2018. We describe the preliminary design and its requirements and report future plans. This upgrade will not only improve our current adaptive optics system but also be the first step toward the future laser tomography and ground layer adaptive optics system at Subaru Telescope.

  59. X-ray-bright optically faint active galactic nuclei in the Subaru Hyper Suprime-Cam wide survey 査読有り

    Yuichi Terashima, Makoto Suganuma, Masayuki Akiyama, Jenny E. Greene, Toshihiro Kawaguchi, Kazushi Iwasawa, Tohru Nagao, Hirofumi Noda, Yoshiki Toba, Yoshihiro Ueda, Takuji Yamashita

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 70 (SP1) S36 2018年1月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psx109  

    ISSN:0004-6264

    eISSN:2053-051X

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    We construct a sample of X-ray-bright optically faint active galactic nuclei by combining Subaru Hyper Suprime-Cam, XMM-Newton, and infrared source catalogs. Fifty-three Xray sources satisfying i-band magnitude fainter than 23.5 mag and X-ray counts with the EPIC-PN detector larger than 70 are selected from 9.1 deg(2), and their spectral energy distributions (SEDs) and X-ray spectra are analyzed. Forty-four objects with an X-ray to i-band flux ratio F-X/F-i > 10 are classified as extreme X-ray-to-optical flux sources. Spectral energy distributions of 48 among 53 are represented by templates of type 2 AGNs or star-forming galaxies and show the optical signature of stellar emission from host galaxies in the source rest frame. Infrared/optical SEDs indicate a significant contribution of emission from dust to the infrared fluxes, and that the central AGN is dust obscured. The photometric redshifts determined from the SEDs are in the range of 0.6-2.5. The X-ray spectra are fitted by an absorbed power-law model, and the intrinsic absorption column densities are modest (best-fit logN(H) = 20.5-23.5 cm(-2) in most cases). The absorption-corrected X-ray luminosities are in the range of 6 x 10(42)-2 x 10(45) erg s(-1). Twenty objects are classified as type 2 quasars based on X-ray luminsosity and N-H. The optical faintness is explained by a combination of redshifts (mostly z > 1.0), strong dust extinction, and in part a large ratio of dust/gas.

  60. Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). II. Discovery of 32 quasars and luminous galaxies at 5.7 < z ≤ 6.8 査読有り

    Matsuoka, Yoshiki, Onoue, Masafusa, Kashikawa, Nobunari, Iwasawa, Kazushi, Strauss, Michael A, Nagao, Tohru, Imanishi, Masatoshi, Lee, Chien-Hsiu, Akiyama, Masayuki, Asami, Naoko

    Publications of the Astronomical Society of Japan 70 S35 2018年1月

    出版者・発行元:None

    DOI: 10.1093/pasj/psx046  

    ISSN:0004-6264

    eISSN:2053-051X

  61. The quasar luminosity function at redshift 4 with the Hyper Suprime-Cam Wide Survey 査読有り

    Masayuki Akiyama, Wanqiu He, Hiroyuki Ikeda, Mana Niida, Tohru Nagao, James Bosch, Jean Coupon, Motohiro Enoki, Masatoshi Imanishi, Nobunari Kashikawa, Toshihiro Kawaguchi, Yutaka Komiyama, Chien-Hsiu Lee, Yoshiki Matsuoka, Satoshi Miyazaki, Atsushi J. Nishizawa, Masamune Oguri, Yoshiaki Ono, Masafusa Onoue, Masami Ouchi, Andreas Schulze, John D. Silverman, Manobu M. Tanaka, Masayuki Tanaka, Yuichi Terashima, Yoshiki Toba, Yoshihiro Ueda

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 70 (SP1) S34 2018年1月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psx091  

    ISSN:0004-6264

    eISSN:2053-051X

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    We present the luminosity function of z similar to 4 quasars based on the Hyper Suprime-Cam Subaru Strategic Program Wide layer imaging data in the g, r, i, z, and y bands covering 339.8 deg(2). From stellar objects, 1666 z similar to 4 quasar candidates are selected via the g-dropout selection down to i = 24.0 mag. Their photometric redshifts cover the red-shift range between 3.6 and 4.3, with an average of 3.9. In combination with the quasar sample from the Sloan Digital Sky Survey in the same redshift range, a quasar luminosity function covering the wide luminosity range of M-1450 = -22 to -29 mag is constructed. The quasar luminosity function is well described by a double power-law model with a knee at M-1450 = -25.36 +/- 0.13mag and a flat faint-end slope with a power-law index of -1.30 +/- 0.05. The knee and faint-end slope show no clear evidence of redshift evolution from those seen at z similar to 2. The flat slope implies that the UV luminosity density of the quasar population is dominated by the quasars around the knee, and does not support the steeper faint-end slope at higher redshifts reported at z > 5. If we convert the M-1450 luminosity function to the hard X-ray 2-10 keV luminosity function using the relation between the UV and X-ray luminosity of quasars and its scatter, the number density of UV-selected quasars matches well with that of the X-ray-selected active galactic nuclei (AGNs) above the knee of the luminosity function. Below the knee, the UV-selected quasars show a deficiency compared to the hard X-ray luminosity function. The deficiency can be explained by the lack of obscured AGNs among the UV-selected quasars.

  62. Clustering of quasars in a wide luminosity range at redshift 4 with Subaru Hyper Suprime-Cam Wide-field imaging 査読有り

    Wanqiu He, Masayuki Akiyama, James Bosch, Motohiro Enoki, Yuichi Harikane, Hiroyuki Ikeda, Nobunari Kashikawa, Toshihiro Kawaguchi, Yutaka Komiyama, Chien-Hsiu Lee, Yoshiki Matsuoka, Satoshi Miyazaki, Tohru Nagao, Masahiro Nagashima, Mana Niida, Atsushi J. Nishizawa, Masamune Oguri, Masafusa Onoue, Taira Oogi, Masami Ouchi, Andreas Schulze, Yuji Shirasaki, John D. Silverman, Manobu M. Tanaka, Masayuki Tanaka, Yoshiki Toba, Hisakazu Uchiyama, Takuji Yamashita

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 70 (SP1) S33 2018年1月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psx129  

    ISSN:0004-6264

    eISSN:2053-051X

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    We examine the clustering of quasars over a wide luminosity range, by utilizing 901 quasars at (Z) over bar (phot) similar to 3.8 with -24.73 < M-1450 < -22.23 photometrically selected from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) S16A Wide2 date release and 342 more luminous quasars at 3.4 < z(spec) < 4.6 with -28.0 < M-1450 < -23.95 from the Sloan Digital Sky Survey that fall in the HSC survey fields. We measure the bias factors of two quasar samples by evaluating the cross-correlation functions (CCFs) between the quasar samples and 25790 bright z similar to 4 Lyman break galaxies in M-1450 < -21.25 photometrically selected from the HSC dataset. Over an angular scale of 10".0 to 1000".0, the bias factors are 5.93(-1.43)(+1.34) and 2.73(-2.55)(+2.44) for the low-and high-luminosity quasars, respectively, indicating no significant luminosity dependence of quasar clustering at z similar to 4. It is noted that the bias factor of the luminous quasars estimated by the CCF is smaller than that estimated by the auto-correlation function over a similar redshift range, especially on scales below 40".0. Moreover, the bias factor of the less-luminous quasars implies the minimal mass of their host dark matter halos is 0.3-2 x 10(12) h(-1)M(circle dot), corresponding to a quasar duty cycle of 0.001-0.06.

  63. Luminous quasars do not live in the most overdense regions of galaxies at z ˜ 4 査読有り

    Uchiyama, Hisakazu, Toshikawa, Jun, Kashikawa, Nobunari, Overzier, Roderik, Chiang, Yi-Kuan, Marinello, Murilo, Tanaka, Masayuki, Niino, Yuu, Ishikawa, Shogo, Onoue, Masafusa, Akiyama, Masayuki, al

    Publications of the Astronomical Society of Japan 70 (SP1) S32 2018年1月

    出版者・発行元:None

    DOI: 10.1093/pasj/psx112  

    ISSN:0004-6264

    eISSN:2053-051X

  64. Enhancement of galaxy overdensity around quasar pairs at z < 3.6 based on the Hyper Suprime-Cam Subaru Strategic Program Survey 査読有り

    Masafusa Onoue, Nobunari Kashikawa, Hisakazu Uchiyama, Masayuki Akiyama, Yuichi Harikane, Masatoshi Imanishi, Yutaka Komiyama, Yoshiki Matsuoka, Tohru Nagao, Atsushi J. Nishizawa, Masamune Oguri, Masami Ouchi, Masayuki Tanaka, Yoshiki Toba, Jun Toshikawa

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 70 (SP1) S31 2018年1月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psx092  

    ISSN:0004-6264

    eISSN:2053-051X

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    ` We investigate the galaxy overdensity around proto-cluster scale quasar pairs at high (z > 3) and low (z similar to 1) redshift based on the unprecedentedly wide and deep optical survey of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). Using the first-year survey data covering effectively similar to 121 deg(2) with the 5 sigma depth of i similar to 26.4 and the SDSS DR12Q catalog, we find two luminous pairs at z similar to 3.3 and 3.6 which reside in > 5s overdensity regions of g-dropout galaxies at i < 25. The projected separations of the two pairs are R-perpendicular to = 1.75 and 1.04 proper Mpc (pMpc), and their velocity offsets are Delta V = 692 and 1448 kms(-1), respectively. This result is in clear contrast to the average z similar to 4 quasar environments as discussed in Uchiyama et al. (2018, PASJ 70, S32) and implies that the quasar activities of the pair members are triggered via major mergers in proto-clusters, unlike the vast majority of isolated quasars in general fields that may turn on via non-merger events such as bar and disk instabilities. At z similar to 1, we find 37 pairs with R-perpendicular to < 2 pMpc and Delta V < 2300 kms(-1) in the current HSC-Wide coverage, including four from Hennawi et al. (2006, AJ, 131, 1). The distribution of the peak overdensity significance within two arcminutes around the pairs has a long tail toward high-density (>4 sigma) regions. Thanks to the large sample size, we find statistical evidence that this excess is unique to the pair environments when compared to single-quasar and randomly selected galaxy environments at the same redshift range. Moreover, there are nine small-scale (R-perpendicular to < 1 pMpc) pairs, two of which are found to reside in cluster fields. Our results demonstrate that <2 pMpc scale quasar pairs at both redshift ranges tend to occur in massive haloes, although perhaps not the most massive ones, and that they are useful in searching for rare density peaks.

  65. Clustering of galaxies around AGNs in the HSC Wide survey 査読有り

    Yuji Shirasaki, Masayuki Akiyama, Tohru Nagao, Yoshiki Toba, Wanqiu He, Masatoshi Ohishi, Yoshihiko Mizumoto, Satoshi Miyazaki, Atsushi J. Nishizawa, Tomonori Usuda

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 70 (SP1) S30 2018年1月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psx099  

    ISSN:0004-6264

    eISSN:2053-051X

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    We have measured the clustering of galaxies around active galactic nuclei (AGNs) for which single-epoch virial masses of the super-massive black hole (SMBH) are available to investigate the relation between the large-scale environment of AGNs and the evolution of SMBHs. The AGN samples used in this work were derived from the Sloan Digital Sky Survey (SDSS) observations and the galaxy samples were from the 240 deg(2) S15b data of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). The investigated redshift range is 0.6-3.0, and the masses of the SMBHs lie in the range 10(7.5)-10(10) M-circle dot. The absolute magnitude of the galaxy samples reaches to M-lambda 310 similar to -18 at rest-frame wavelength 310 nm for the low-redshift end of the samples. More than 70% of the galaxies in the analysis are blue. We found a significant dependence of the cross-correlation length on redshift, which primarily reflects the brightness-dependence of the galaxy clustering. At the lowest redshifts the cross-correlation length increases from 7 h(-1) Mpc around M-lambda 310 = -19 mag to > 10 h(-1) Mpc beyond M-lambda 310 = -20 mag. No significant dependence of the cross-correlation length on BH mass was found for whole galaxy samples dominated by blue galaxies, while there was an indication of BH mass dependence in the cross-correlation with red galaxies. These results provides a picture of the environment of AGNs studied in this paper being enriched with blue star-forming galaxies, and a fraction of the galaxies are evolving into red galaxies along with the evolution of SMBHs in that system.

  66. GOLDRUSH. III. A systematic search for protoclusters at z ˜ 4 based on the >100 deg2 area 査読有り

    Toshikawa, Jun, Uchiyama, Hisakazu, Kashikawa, Nobunari, Ouchi, Masami, Overzier, Roderik, Ono, Yoshiaki, Harikane, Yuichi, Ishikawa, Shogo, Kodama, Tadayuki, Matsuda, Yuichi, Akiyama, Masayuki, al

    Publications of the Astronomical Society of Japan 70 (SP1) S12 2018年1月

    出版者・発行元:None

    DOI: 10.1093/pasj/psx102  

    ISSN:0004-6264

    eISSN:2053-051X

  67. GOLDRUSH. II. Clustering of galaxies at z ˜ 4-6 revealed with the half-million dropouts over the 100 deg2 area corresponding to 1 Gpc3 査読有り

    Harikane, Yuichi, Ouchi, Masami, Ono, Yoshiaki, Saito, Shun, Behroozi, Peter, More, Surhud, Shimasaku, Kazuhiro, Toshikawa, Jun, Lin, Yen-Ting, Akiyama, Masayuki, al

    Publications of the Astronomical Society of Japan 70 (SP1) S11 2018年1月

    出版者・発行元:None

    DOI: 10.1093/pasj/psx097  

    ISSN:0004-6264

    eISSN:2053-051X

  68. Great Optically Luminous Dropout Research Using Subaru HSC (GOLDRUSH). I. UV luminosity functions at z ˜ 4-7 derived with the half-million dropouts on the 100 deg2 sky 査読有り

    Ono, Yoshiaki, Ouchi, Masami, Harikane, Yuichi, Toshikawa, Jun, Rauch, Michael, Yuma, Suraphong, Sawicki, Marcin, Shibuya, Takatoshi, Shimasaku, Kazuhiro, Oguri, Masamune, Akiyama, Masayuki, al

    Publications of the Astronomical Society of Japan 70 (SP1) S10 2018年1月

    出版者・発行元:None

    DOI: 10.1093/pasj/psx103  

    ISSN:0004-6264

    eISSN:2053-051X

  69. ALMA 26 arcmin<SUP>2</SUP> Survey of GOODS-S at One-millimeter (ASAGAO): X-Ray AGN Properties of Millimeter-selected Galaxies 査読有り

    Ueda, Y., Hatsukade, B., Kohno, K., Yamaguchi, Y., Tamura, Y., Umehata, H., Akiyama, M., Ao, Y., Aretxaga, I., Caputi, K., Dunlop, J. S., Espada, D., Fujimoto, S., Hayatsu, N. H., Imanishi, M., Inoue, A. K., Ivison, R. J., Kodama, T., Lee, M. M., Matsuoka, K., Miyaji, T., Morokuma-Matsui, K., Nagao, T., Nakanishi, K., Nyland, K., Ohta, K., Ouchi, M., Rujopakarn, W., Saito, T., Tadaki, K., Tanaka, I., Taniguchi, Y., Wang, T., Wang, W. -H., Yoshimura, Y., Yun, M. S.

    The Astrophysical Journal 853 (1) 24-11 2018年1月

    出版者・発行元:American Astronomical Society

    DOI: 10.3847/1538-4357/aa9f10  

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    We investigate the X-ray active galactic nucleus (AGN) properties of millimeter galaxies in the Great Observatories Origins Deep Survey South (GOODS-S) field detected with the Atacama Large Millimeter/submillimeter Array (ALMA), by utilizing the Chandra 7-Ms data, the deepest X-ray survey to date. Our millimeter galaxy sample comes from the ASAGAO survey covering 26 arcmin<SUP>2</SUP> (12 sources at a 1.2 mm flux-density limit of ≈ 0.6 mJy), supplemented by the deeper but narrower 1.3 mm survey of a part of the ASAGAO field by Dunlop et al. Ofthe 25 total millimeter galaxies, 14 have Chandra counterparts. The observed AGN fractions at z=1.5{--}3 are found to be {90}<SUB>-19</SUB><SUP>+8</SUP>% and {57}<SUB>-25</SUB><SUP>+23</SUP>% for the ultra-luminous and luminous infrared galaxies with log {L}<SUB>{IR</SUB>}/{L}<SUB>☉ </SUB> = 12-12.8 and log {L}<SUB>{IR</SUB>}/{L}<SUB>☉ </SUB> = 11.5-12, respectively. The majority (̃2/3) of the ALMA and/or Herschel detected X-ray AGNs at z = 1.5-3 appear to be star-formation-dominant populations, having {L}<SUB>{ { X</SUB> } }/ {L}<SUB>{IR</SUB>} ratios smaller than the “simultaneous evolution” value expected from the local black-hole-mass-to-stellar-mass ({M}<SUB>{BH</SUB>}-M <SUB>*</SUB>) relation. On the basis of the {L}<SUB>{ { X</SUB> } } and stellar mass relation, we infer that a large fraction of star-forming galaxies at z=1.5{--}3 have black hole masses that are smaller than those expected from the local {M}<SUB>{BH</SUB>}-M <SUB>*</SUB> relation. This contrasts previous reports on luminous AGNs at the same redshifts detected in wider and shallower surveys, which are subject to selection biases against lower luminosity AGNs. Our results are consistent with an evolutionary scenario in which star formation occurs first, and an AGN-dominant phase follows later, in objects that finally evolve into galaxies with classical bulges....

  70. An Optically Faint Quasar Survey at z ˜ 5 in the CFHTLS Wide Field: Estimates of the Black Hole Masses and Eddington Ratios 査読有り

    Ikeda, H, Nagao, T, Matsuoka, K, Kawakatu, N, Kajisawa, M, Akiyama, M, Miyaji, T, Morokuma, T

    The Astrophysical Journal 846 (1) 57-16 2017年9月

    出版者・発行元:None

    DOI: 10.3847/1538-4357/aa83ae  

    ISSN:0004-637X

    eISSN:1538-4357

  71. Understanding the scatter in the spatially resolved star formation main sequence of local massive spiral galaxies 査読有り

    Abdurro'uf, Masayuki Akiyama

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 469 (3) 2806-2820 2017年8月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/mnras/stx936  

    ISSN:0035-8711

    eISSN:1365-2966

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    We investigate the relation between star formation rate (SFR) and stellar mass (M-*) at the sub-galactic scale (similar to 1 kpc) of 93 local (0.01< z < 0.02) massive (M-* > 10(10.5) M-circle dot) spiral galaxies. To derive a spatially resolved SFR and stellar mass, we perform the so-called pixel-to-pixel spectral energy distribution (SED) fitting, which fits an observed spatially resolved multiband SED with a library of model SEDs using Bayesian statistics. We use two bands (far-ultraviolet or FUV and near-ultraviolet or NUV) and five bands (u, g, r, i and z) of imaging data from Galaxy Evolution Explorer (GALEX) and Sloan Digital Sky Survey (SDSS), respectively. We find a tight nearly linear relation between the local surface density of SFR (Sigma(SFR)) and stellar mass (Sigma(*)), which is flattened at high Sigma(*). The near linear relation between Sigma(*) and Sigma(SFR) suggests a constant specific SFR (sSFR) throughout the galaxies, and the scatter of the relation is directly related to that of the sSFR. Therefore, we analyse the variation of the sSFR in various scales. More massive galaxies on average have lower sSFR throughout them than less massive galaxies. We also find that barred galaxies have a lower sSFR in the core region than non-barred galaxies. However, in the outer region, the sSFRs of barred and non-barred galaxies are similar and lead to a similar total sSFR.

  72. Far-infrared Properties of Infrared-bright Dust-obscured Galaxies Selected with IRAS and AKARI Far-infrared All-sky Survey 査読有り

    Yoshiki Toba, Tohru Nagao, Wei-Hao Wang, Hideo Matsuhara, Masayuki Akiyama, Tomotsugu Goto, Yusei Koyama, Youich Ohyama, Issei Yamamura

    ASTROPHYSICAL JOURNAL 840 (1) 21 2017年5月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/aa6d0a  

    ISSN:0004-637X

    eISSN:1538-4357

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    We investigate the star-forming activity of a sample of infrared (IR)-bright dust-obscured galaxies (DOGs) that show an extreme red color in the optical and IR regime, (i - [22])(AB) > 7.0. Combining an IR-bright DOG sample with the flux at 22 mu m. > 3.8 mJy discovered by Toba & Nagao with the IRAS faint source catalog version 2 and AKARI far-IR (FIR) all-sky survey bright source catalog version 2, we selected 109 DOGs with FIR data. For a subsample of seven IR-bright DOGs with spectroscopic redshifts (0.07 < z < 1.0) that were obtained from the literature, we estimated their IR luminosity, star formation rate (SFR), and stellar mass based on the spectral energy distribution fitting. We found that (1) the WISE 22 mu m luminosity at the observed frame is a good indicator of IR luminosity for IR-bright DOGs and (2) the contribution of the active galactic nucleus to IR luminosity increases with IR luminosity. By comparing the stellar mass and SFR relation for our DOG sample and the literature, we found that most of the IR-bright DOGs lie significantly above the main sequence of star-forming galaxies at similar redshift, indicating that the majority of IRAS-or AKARI-detected IR-bright DOGs are starburst galaxies.

  73. Using the multi-object adaptive optics demonstrator RAVEN to observe metal-poor stars in and towards the Galactic Centre 査読有り

    M. Lamb, K. Venn, D. Andersen, S. Oya, M. Shetrone, A. Fattahi, L. Howes, M. Asplund, O. Lardiere, M. Akiyama, Y. Ono, H. Terada, Y. Hayano, G. Suzuki, C. Blain, K. Jackson, C. Correia, K. Youakim, C. Bradley

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 465 (3) 3536-3557 2017年3月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/mnras/stw2865  

    ISSN:0035-8711

    eISSN:1365-2966

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    The chemical abundances for five metal-poor stars in and towards the Galactic bulge have been determined from the H-band infrared spectroscopy taken with the RAVEN multi-object adaptive optics science demonstrator and the Infrared Camera and Spectrograph at the Subaru 8.2- m telescope. Three of these stars are in the Galactic bulge and have metallicities between - 2.1&lt;[Fe/H]&lt; - 1.5, and high [alpha/ Fe]similar to+ 0.3, typical of Galactic disc and bulge stars in this metallicity range; [Al/ Fe] and [N/ Fe] are also high, whereas [C/ Fe] &lt; + 0.3. An examination of their orbits suggests that two of these stars may be confined to the Galactic bulge and one is a halo trespasser, though proper motion values used to calculate orbits are quite uncertain. An additional two stars in the globular cluster M22 show [ Fe/H] values consistent to within 1 sigma, although one of these two stars has [ Fe/H] = - 2.01 +/- 0.09, which is on the low end for this cluster. The [a/ Fe] and [Ni/ Fe] values differ by 2 sigma, with the most metal-poor star showing significantly higher values for these elements. M22 is known to show element abundance variations, consistent with a multipopulation scenario though our results cannot discriminate this clearly given our abundance uncertainties. This is the first science demonstration of multiobject adaptive optics with high-resolution infrared spectroscopy, and we also discuss the feasibility of this technique for use in the upcoming era of 30-m class telescope facilities.

  74. Statistics of turbulence parameters at Maunakea using the multiple wavefront sensor data of RAVEN 査読有り

    Yoshito H. Ono, Carlos M. Correia, Dave R. Andersen, Olivier Lardiere, Shin Oya, Masayuki Akiyama, Kate Jackson, Colin Bradley

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 465 (4) 4931-4941 2017年3月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/mnras/stw3083  

    ISSN:0035-8711

    eISSN:1365-2966

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    Prior statistical knowledge of atmospheric turbulence is essential for designing, optimizing and evaluating tomographic adaptive optics systems. We present the statistics of the vertical profiles of C-N(2) and the outer scale at Maunakea estimated using a SLOpe Detection And Ranging (SLODAR) method from on-sky telemetry taken by a multi-object adaptive optics (MOAO) demonstrator, called RAVEN, on the Subaru telescope. In our SLODAR method, the profiles are estimated by fitting the theoretical autocorrelations and cross-correlations of measurements from multiple Shack Haltmann wavefront sensors to the observed correlations via the non-linear Levenberg Marquardt Algorithm (LMA). The analytical derivatives of the spatial phase structure function with respect to its parameters for the LMA are also developed. From a total of 12 nights in the summer season, a large ground C-N(2) fraction of 54.3 per cent is found, with median estimated seeing of 0.460 arcsec. This median seeing value is below the results for Maunakea from the literature (0.6-0.7 arcsec). The average C-N(2) profile is in good agreement with results from the literature, except for the ground layer. The median value of the outer scale is 25.5 m and the outer scale is larger at higher altitudes; these trends of the outer scale are consistent with findings in the literature.

  75. CLUSTERING OF INFRARED-BRIGHT DUST-OBSCURED GALAXIES REVEALED BY THE HYPER SUPRIME-CAM AND WISE 査読有り

    Yoshiki Toba, Tohru Nagao, Masaru Kajisawa, Taira Oogi, Masayuki Akiyama, Hiroyuki Ikeda, Jean Coupon, Michael A. Strauss, Wei-Hao Wang, Masayuki Tanaka, Mana Niida, Masatoshi Imanishi, Chien-Hsiu Lee, Hideo Matsuhara, Yoshiki Matsuoka, Masafusa Onoue, Yuichi Terashima, Yoshihiro Ueda, Yuichi Harikane, Yutaka Komiyama, Satoshi Miyazaki, Akatoki Noboriguchi, Tomonori Usuda

    ASTROPHYSICAL JOURNAL 835 (1) 36-12pp 2017年1月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/835/1/36  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present measurements of the clustering properties of a sample of infrared (IR) bright dust-obscured galaxies (DOGs). Combining 125 deg(2) of wide and deep optical images obtained with the Hyper Suprime-Cam on the Subaru Telescope and all-sky mid-IR images taken with Wide-Field Infrared Survey Explorer, we have discovered 4367 IR-bright DOGs with (i - [22])(AB) > 7.0 and flux density at 22 mu m > 1.0 mJy. We calculate the angular autocorrelation function (ACF) for a uniform subsample of 1411 DOGs with 3.0 mJy < flux (22 mu m) < 5.0 mJy and i(AB) < 24.0. The ACF of our DOG subsample is well-fit with a single power law, w(theta) = (0.010 +/- 0.003)theta(-0.9), where theta is in degrees. The correlation amplitude of IR-bright DOGs is larger than that of IR-faint DOGs, which reflects a flux dependence of the DOG clustering, as suggested by Brodwin et al. We assume that the redshift distribution for our DOG sample is Gaussian, and consider two cases: (1) the redshift distribution is the same as IR-faint DOGs with flux at 22 mu m < 1.0 mJy, mean and sigma z = 1.99 +/- 0.45, and (2) z = 1.19 +/- 0.30, as inferred from their photometric redshifts. The inferred correlation length of IR-bright DOGs is r(0) = 12.0 +/- 2.0 and 10.3 +/- 1.7 h(-1) Mpc, respectively. IR-bright DOGs reside in massive dark matter halos with a mass of log [ M-h /(h(-1) M-circle dot)] = 13.57(-0.55)(+0.50) and 13.65(-0.52)(+0.45) in the two cases, respectively.

  76. CLUSTER GLIMPSES WITH RAVEN: AO-CORRECTED NEAR AND MID-INFRARED IMAGES OF GLIMPSE C01 AND GLIMPSE C02 査読有り

    T. J. Davidge, D. R. Andersen, O. Lardiere, C. Bradley, C. Blain, S. Oya, H. Terada, Y. Hayano, M. Lamb, M. Akiyama, Y. H. Ono, G. Suzuki

    ASTRONOMICAL JOURNAL 152 (6) 173-19pp 2016年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/0004-6256/152/6/173  

    ISSN:0004-6256

    eISSN:1538-3881

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    We discuss images of the star clusters GLIMPSE C01 (GC01) and GLIMPSE C02 (GC02) that were recorded with the Subaru IRCS. Distortions in the wavefront were corrected with the RAVEN adaptive optics (AO) science demonstrator, allowing individual stars in the central regions of both clusters-where the fractional contamination from non-cluster objects is lowest-to be imaged. In addition to J, H, and K' images, both clusters were observed through a narrow-band filter centered near 3.05 mu m; GC01 was also observed through two other narrow-band filters that sample longer wavelengths. Stars in the narrow-band images have an FWHM that is close to the telescope diffraction limit, demonstrating that open-loop AO systems like RAVEN can deliver exceptional image quality. The near-infrared color-magnitude diagram of GC01 is smeared by non-uniform extinction with a 1 sigma dispersion Delta A(K) = +/- 0.13 mag. Spatial variations in A(K) are not related in a systematic way to location in the field. The Red Clump is identified in the K luminosity function (LF) of GC01, and a distance modulus of 13.6 is found. The K LF of GC01 is consistent with a system that is dominated by stars with an age &gt; 1 Gyr. As for GC02, the K LF is flat for K. &gt;. 16, and the absence of a sub-giant branch argues against an old age if the cluster is at a distance of similar to 7 kpc. Archival SPITZER [3.6] and [4.5] images of the clusters are also examined, and the red giant branch-tip is identified. It is demonstrated in the Appendix that the [3.6] surface brightness profiles of both clusters can be traced out to radii of at least 100 arcsec.

  77. CONSTRAINT ON THE INFLOW/OUTFLOW RATES IN STAR-FORMING GALAXIES AT z similar to 1.4 FROM MOLECULAR GAS OBSERVATIONS 査読有り

    Akifumi Seko, Kouji Ohta, Kiyoto Yabe, Bunyo Hatsukade, Masayuki Akiyama, Naoyuki Tamura, Fumihide Iwamuro, Gavin Dalton

    ASTROPHYSICAL JOURNAL 833 (1) 53-5pp 2016年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/1538-4357/833/1/53  

    ISSN:0004-637X

    eISSN:1538-4357

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    We constrain the rate of gas inflow into and outflow from a main-sequence star-forming galaxy at z similar to 1.4 by fitting a simple analytic model for the chemical evolution in a galaxy to the observational data of the stellar mass, metallicity, and molecular gas mass fraction. The molecular gas mass is derived from CO observations with a metallicity-dependent CO-to-H-2 conversion factor, and the gas metallicity is derived from the H alpha and [N II]lambda 6584 emission line ratio. Using a stacking analysis of CO integrated intensity maps and the emission lines of H alpha and [N II], the relation between stellar mass, metallicity, and gas mass fraction is derived. We constrain the inflow and outflow rates with least-chi-square fitting of a simple analytic chemical evolution model to the observational data. The best-fit inflow and outflow rates are similar to 1.7 and similar to 0.4 in units of star formation rate (SFR), respectively. The inflow rate is roughly comparable to the sum of the SFR and outflow rate, which supports the equilibrium model for galaxy evolution; i.e., all inflow gas is consumed by star formation and outflow.

  78. A NEW MILKY WAY SATELLITE DISCOVERED IN THE SUBARU/HYPER SUPRIME-CAM SURVEY 査読有り

    Daisuke Homma, Masashi Chiba, Sakurako Okamoto, Yutaka Komiyama, Masayuki Tanaka, Mikito Tanaka, Miho N. Ishigaki, Masayuki Akiyama, Nobuo Arimoto, Jose A. Garmilla, Robert H. Lupton, Michael A. Strauss, Hisanori Furusawa, Satoshi Miyazaki, Hitoshi Murayama, Atsushi J. Nishizawa, Masahiro Takada, Tomonori Usuda, Shiang-Yu Wang

    ASTROPHYSICAL JOURNAL 832 (1) 21 2016年11月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/0004-637X/832/1/21  

    ISSN:0004-637X

    eISSN:1538-4357

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    We report the discovery of a new ultra-faint dwarf satellite companion of the Milky Way (MW) based on the early survey data from the Hyper Suprime-Cam Subaru Strategic Program. This new satellite, Virgo. I, which is located in the constellation of Virgo, has been identified as a statistically significant (5.5 sigma) spatial overdensity of star-like objects with a well-defined main sequence and red giant branch in the. color-magnitude diagram. The significance of this overdensity increases to 10.8 sigma when the relevant isochrone filter is adopted for the search. Based on the distribution of the stars around the likely main-sequence turnoff at r similar to 24 mag, the distance to Virgo. I is estimated as 87 kpc, and its most likely absolute magnitude calculated from a Monte Carlo analysis is M-V =. -0.8 +/- 0.9 mag. This stellar system has an extended spatial distribution with a half-light radius of 38(-11)(+12) pc, which clearly distinguishes it from a globular cluster with comparable luminosity. Thus, Virgo. I is one of the faintest dwarf satellites known and is located beyond the reach of the Sloan Digital Sky Survey. This demonstrates the power of this survey program to identify very faint dwarf satellites. This discovery of Virgo. I is based only on about 100 square degrees of data, thus a large number of faint dwarf satellites are likely to exist in the outer halo of the MW.

  79. SUBARU HIGH-z EXPLORATION OF LOW-LUMINOSITY QUASARS (SHELLQs). I. DISCOVERY OF 15 QUASARS AND BRIGHT GALAXIES AT 5.7 < z < 6.9 査読有り

    Yoshiki Matsuoka, Masafusa Onoue, Nobunari Kashikawa, Kazushi Iwasawa, Michael A. Strauss, Tohru Nagao, Masatoshi Imanishi, Mana Niida, Yoshiki Toba, Masayuki Akiyama, Naoko Asami, James Bosch, Sebastien Foucaud, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Toshihiro Kawaguchi, Satoshi Kikuta, Yutaka Komiyama, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Tomoki Morokuma, Hitoshi Murayama, Atsushi J. Nishizawa, Yoshiaki Ono, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, John D. Silverman, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Tadafumi Takata, Masayuki Tanaka, Ji-Jia Tang, Yousuke Utsumi

    ASTROPHYSICAL JOURNAL 828 (1) 26-14pp 2016年9月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/0004-637X/828/1/26  

    ISSN:0004-637X

    eISSN:1538-4357

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    We report the discovery of 15 quasars and bright galaxies at 5.7 < z < 6.9. This is the initial result from the Subaru High-z Exploration of Low-Luminosity Quasars project, which exploits the exquisite multiband imaging data produced by the Subaru Hyper Suprime-Cam (HSC) Strategic Program survey. The candidate selection is performed by combining several photometric approaches including a Bayesian probabilistic algorithm to reject stars and dwarfs. The spectroscopic identification was carried out with the Gran Telescopio Canarias and the Subaru Telescope for the first 80 deg(2) of the survey footprint. The success rate of our photometric selection is quite high, approaching 100% at the brighter magnitudes (z(AB) < 23.5 mag). Our selection also recovered all the known high-z quasars on the HSC images. Among the 15 discovered objects, six are likely quasars, while the other six with interstellar absorption lines and in some cases narrow emission lines are likely bright Lyman-break galaxies. The remaining three objects have weak continua and very strong and narrow Ly alpha lines, which may be excited by ultraviolet light from both young stars and quasars. These results indicate that we are starting to see the steep rise of the luminosity function of z >= 6 galaxies, compared with that of quasars, at magnitudes fainter than M-1450 similar to -22 mag or z(AB) similar to 24 mag. Follow-up studies of the discovered objects as well as further survey observations are ongoing.

  80. The Subaru FMOS galaxy redshift survey (FastSound). II. The emission line catalog and properties of emission line galaxies 査読有り

    Hiroyuki Okada, Tomonori Totani, Motonari Tonegawa, Masayuki Akiyama, Gavin Dalton, Karl Glazebrook, Fumihide Iwamuro, Kouji Ohta, Naruhisa Takato, Naoyuki Tamura, Kiyoto Yabe, Andrew J. Bunker, Tomotsugu Goto, Chiaki Hikage, Takashi Ishikawa, Teppei Okumura, Ikkoh Shimizu

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 68 (3) 47-17pp 2016年6月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psw043  

    ISSN:0004-6264

    eISSN:2053-051X

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    We present basic properties of similar to 3300 emission line galaxies detected by the FastSound survey, which aremostly Ha emitters at z similar to 1.2-1.5 in the total area of about 20 deg(2), with the Ha flux sensitivity limit of similar to 1.6 x 10(-16) erg cm(-2) s(-1) at 4.5 sigma. This paper presents the catalog of the FastSound emission lines and galaxies, which is open to the public. We also present basic properties of typical FastSound Ha emitters, which have Ha luminosities of 10(41.8)-10(43.3) erg s(-1), star formation rates (SFRs) of 20-500 M-circle dot yr(-1), and stellar masses of 10(10.0)-10(11.3) M-circle dot. The 3D distribution maps for the four fields of Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) W1-4 are presented, clearly showing large scale clustering of galaxies at the scale of similar to 100-600 comoving Mpc. Based on 1105 galaxies with detections of multiple emission lines, we estimate that the contamination of non-H alpha lines is about 4% in the single-line emission galaxies, which is mostly [O (III)]lambda 5007. This contamination fraction is also confirmed by the stacked spectrum of all the FastSound spectra, in which H alpha, [N (II)]lambda lambda 6548,6583, [S (II)]lambda lambda 6717,6731, and [O (I)]lambda lambda 6300,6364 are seen.

  81. The Subaru FMOS galaxy redshift survey (FastSound). IV. New constraint on gravity theory from redshift space distortions at z similar to 1.4 査読有り

    Teppei Okumura, Chiaki Hikage, Tomonori Totani, Motonari Tonegawa, Hiroyuki Okada, Karl Glazebrook, Chris Blake, Pedro G. Ferreira, Surhud More, Atsushi Taruya, Shinji Tsujikawa, Masayuki Akiyama, Gavin Dalton, Tomotsugu Goto, Takashi Ishikawa, Fumihide Iwamuro, Takahiko Matsubara, Takahiro Nishimichi, Kouji Ohta, Ikkoh Shimizu, Ryuichi Takahashi, Naruhisa Takato, Naoyuki Tamura, Kiyoto Yabe, Naoki Yoshida

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 68 (3) 38-24pp 2016年6月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psw029  

    ISSN:0004-6264

    eISSN:2053-051X

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    We measure the redshift-space correlation function from a spectroscopic sample of 2783 emission line galaxies from the FastSound survey. The survey, which uses the Subaru Telescope and covers a redshift range of 1.19 < z < 1.55, is the first cosmological study at such high redshifts. We detect clear anisotropy due to redshift-space distortions (RSD) both in the correlation function as a function of separations parallel and perpendicular to the line of sight and its quadrupole moment. RSD has been extensively used to test general relativity on cosmological scales at z < 1. Adopting a Lambda CDM cosmology with the fixed expansion history and no velocity dispersion (sigma(v) = 0), and using the RSD measurements on scales above 8 h(-1) Mpc, we obtain the first constraint on the growth rate at the redshift, f(z)sigma(8)(z) = 0.482 +/- 0.116 at z similar to 1.4 after marginalizing over the galaxy bias parameter b(z)sigma(8)(z). This corresponds to 4.2 sigma detection of RSD. Our constraint is consistent with the prediction of general relativity f sigma(8) similar to 0.392 within the 1 sigma confidence level. When we allow sv to vary and marginalize over it, the growth rate constraint becomes f sigma(8) = 0.494(-0.120)(+0.126). We also demonstrate that by combining with the low-z constraints on f sigma(8), high-z galaxy surveys like the FastSound can be useful to distinguish modified gravity models without relying on CMB anisotropy experiments.

  82. Multi time-step wavefront reconstruction for tomographic adaptive-optics systems 査読有り

    Yoshito H. Ono, Masayuki Akiyama, Shin Oya, Olivier Lardiere, David R. Andersen, Carlos Correia, Kate Jackson, Colin Bradley

    JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 33 (4) 726-740 2016年4月

    出版者・発行元:OPTICAL SOC AMER

    DOI: 10.1364/JOSAA.33.000726  

    ISSN:1084-7529

    eISSN:1520-8532

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    In tomographic adaptive-optics (AO) systems, errors due to tomographic wavefront reconstruction limit the performance and angular size of the scientific field of view (FoV), where AO correction is effective. We propose a multi time-step tomographic wavefront reconstruction method to reduce the tomographic error by using measurements from both the current and previous time steps simultaneously. We further outline the method to feed the reconstructor with both wind speed and direction of each turbulence layer. An end-to-end numerical simulation, assuming a multi-object AO (MOAO) system on a 30 m aperture telescope, shows that the multi time-step reconstruction increases the Strehl ratio (SR) over a scientific FoV of 10 arc min in diameter by a factor of 1.5-1.8 when compared to the classical tomographic reconstructor, depending on the guide star asterism and with perfect knowledge of wind speeds and directions. We also evaluate the multi time-step reconstruction method and the wind estimation method on the RAVEN demonstrator under laboratory setting conditions. The wind speeds and directions at multiple atmospheric layers are measured successfully in the laboratory experiment by our wind estimation method with errors below 2 ms-1. With these wind estimates, the multi time-step reconstructor increases the SR value by a factor of 1.2-1.5, which is consistent with a prediction from the end-to-end numerical simulation. (C) 2016 Optical Society of America

  83. PROPERTIES OF THE INTERSTELLAR MEDIUM IN STAR-FORMING GALAXIES AT z similar to 1.4 REVEALED WITH ALMA 査読有り

    Akifumi Seko, Kouji Ohta, Kiyoto Yabe, Bunyo Hatsukade, Masayuki Akiyama, Fumihide Iwamuro, Naoyuki Tamura, Gavin Dalton

    ASTROPHYSICAL JOURNAL 819 (1) 82-18pp 2016年3月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.3847/0004-637X/819/1/82  

    ISSN:0004-637X

    eISSN:1538-4357

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    We conducted observations of (CO)-C-12(J = 5-4) and dust thermal continuum emission toward 20 star-forming galaxies on the main sequence at z similar to 1.4 using ALMA to investigate the properties of the interstellar medium. The sample galaxies are chosen to trace the distributions of star-forming galaxies in diagrams of stellar mass versus star formation rate and stellar mass versus metallicity. We detected CO emission lines from 11 galaxies. The molecular gas mass is derived by adopting a metallicity-dependent CO-to-H-2 conversion factor and assuming a CO(5-4)/CO (1-0) luminosity ratio of 0.23. Masses of molecular gas and its fractions (molecular gas mass/(molecular gas mass + stellar mass)) for the detected galaxies are in the ranges of (3.9-12) x 10(10) M-circle dot and 0.25-0.94, respectively; these values are significantly larger than those in local spiral galaxies. The molecular gas mass fraction decreases with increasing stellar mass; the relation holds for four times lower stellar mass than that covered in previous studies, and the molecular gas mass fraction decreases with increasing metallicity. Stacking analyses also show the same trends. Dust thermal emissions were clearly detected from two galaxies and marginally detected from five galaxies. Dust masses of the detected galaxies are (3.9-38) x 10(7) M-circle dot. We derived gas-to-dust ratios and found they are 3-4 times larger than those in local galaxies. The depletion times of molecular gas for the detected galaxies are (1.4-36) x 10(8) yr while the results of the stacking analysis show similar to 3 x 10(8) yr. The depletion time tends to decrease with increasing stellar mass and metallicity though the trend is not so significant, which contrasts with the trends in local galaxies.

  84. Star formation activity in Balmer break galaxies at z &lt; 1.5 査読有り

    J. Diaz Tello, C. Donzelli, N. Padilla, M. Akiyama, N. Fujishiro, T. Yoshikawa, H. Hanami

    ASTRONOMY & ASTROPHYSICS 587 (1) 136-20pp 2016年3月

    出版者・発行元:EDP SCIENCES S A

    DOI: 10.1051/0004-6361/201526315  

    ISSN:1432-0746

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    Aims. We present a spectroscopic study of the properties of 64 Balmer break galaxies that show signs of star formation. The studied sample of star-forming galaxies spans a redshift range from. 0.094 to 1.475 with stellar masses in the range 10(8)-0(12) M-circle dot. l'he sample also includes eight broad emission line galaxies with redshifts between 1.5 &lt; z &lt; 3.0. Methods. We derived star formation rates (SFRs) from emission line luminosities and investigated the dependence of the SFR and specific SFR (SSFR) on the stellar mass and color. Furthermore, we investigated the evolution of these relations with the redshift. Results. We found that the SFR correlates with the stellar mass; our data is consistent with previous results from other authors in that there is a break in the correlation, which reveals the presence of massive galaxies with lower SFR values (i.e., decreasing star formation). We also note an anticorrelation for the SSFR with the stellar mass. Again in this case, our data is also consistent with a break in the correlation, revealing the presence of massive star-forming galaxies with lower SSFR values, thereby increasing the anticorrelation. These results might suggest a characteristic mass (M-0) at which the red sequence could mostly be assembled. tn addition, at a given stellar mass, high-redshift galaxies have on average higher SFR and SSFR values than local galaxies. Finally, we explored whether a similar trend could be observed with redshift in the SSFR-(u - B) color diagram, and we hypothesize that a possible (u - B)(0) break color may define a characteristic color for the formation of the red sequence.

  85. Effect of Homogenization Pressure on Sensory Characteristics and Flavor Release of and Preference for Flavored Dairy Beverages

    Toshiyoshi Kawaguchi, Masayuki Akiyama, Masanobu Onishi, Misako Okaue, Reiko Koizumi, Yasumichi Mizota, Teiichiro Okawa, Masahiro Sumi, Hisakatsu Iwabuchi

    JOURNAL OF THE JAPANESE SOCIETY FOR FOOD SCIENCE AND TECHNOLOGY-NIPPON SHOKUHIN KAGAKU KOGAKU KAISHI 63 (1) 25-34 2016年

    出版者・発行元:JAPAN SOC FOOD SCIENCE TECHNOLOGY

    DOI: 10.3136/nskkk.63.25  

    ISSN:1341-027X

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    The effect of homogenization pressure (HP), which can cause fat globule size differences, on sensory characteristics and retronasal-aroma release of and preference for coffee- and strawberry-flavored dairy beverages was investigated by sensory evaluation and gas chromatography-mass spectrometry (GC-MS) analysis using a retronasal aroma simulator (RAS). Each flavored sample was homogenized at 2, 7, and 25 MPa. Sensory characteristics ("sweetness" in coffee; "sweetness", "milk flavor", "thickness", "fattiness", "body" in strawberry) of the flavored samples were significantly (p<0.05) influenced by HP. "Thickness", "fattiness", and "body" attributes of the strawberry samples were enhanced with increasing HP (2<25 MPa). In addition, sensory preferences for coffee flavored dairy beverage were significantly (p < 0.05) influenced by HP. The coffee sample homogenized under higher HP was preferred (2< 25 MPa, 7<25 MPa). Furthermore, GC-MS analysis of the RAS compounds released from milk fat emulsions (MFE), which contained 11 strawberry-flavor compounds and were homogenized at 7, 14, and 35 MPa, revealed that six highly-volatile compounds, which have smaller logP values, significantly (p<0.05) increased with increasing HP (7< 14 MPa). However, there were no significant differences in the sensory characteristics of strawberry-flavored beverages with simulated differences in the six RAS-compound releases between 7 and 14 MPa-homogenized MFEs by adding the six compounds, and homogenized under the same HP (7 MPa). From the above results, it was suggested that the significant effect of HP on the sensory characteristics of flavored beverages was due to not only RAS-compound release but also other factors such as fat globule size.

  86. The Subaru FMOS Galaxy Redshift Survey (FastSound): The Mass-Metallicity Relation and the Fundamental Metallicity Relation at z similar to 1.4

    Kiyoto Yabe, Kouji Ohta, Masayuki Akiyama, Naoyuki Tamura, Fumihide Iwamuro, Tomonori Totani, Gavin Dalton, Andrew Bunker

    MULTI-OBJECT SPECTROSCOPY IN THE NEXT DECADE: BIG QUESTIONS, LARGE SURVEYS, AND WIDE FIELDS 507 355-360 2016年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We present results from a large NIR spectroscopic survey (FastSound) with Subaru/FMOS, consisting of 4,000 galaxies at z similar to 1.4 with significant Ha detection. The resulting mass-metallicity relation generally agrees with those obtained previously in a similar redshift range to our sample. No clear dependence on the massmetallicity relation on star-formation rate is found, which is not in agreement with the extrapolation of the local fundamental metallicity relation. We estimate the nitrogen-to oxygen abundance ratio (N/O) from the N2S2 index, and find that the N/O in galaxies at z 1.4 is significantly higher than the local values at a fixed metallicity and stellar mass. The metallicity derived by using the N2 method calibrated in the local universe decreases by similar to 0.2 dex if we correct the N/O enhancement.

  87. SXDF-UDS-CANDELS-ALMA 1.5 arcmin^2 deep survey

    Kohno, K, Yamaguchi, Y, Tamura, Y, Tadaki, K, Hatsukade, B, Ikarashi, S, Caputi, K. I, Rujopakarn, W, Ivison, R. J, Dunlop, J. S, Motohara, K, Umehata, H, Yabe, K, Wang, W.-H, Kodama, T, Koyama, Y, Hayashi, M, Matsuda, Y, Hughes, D, Aretxaga, I, Wilson, G. W, Yun, M. S, Ohta, K, Akiyama, M, Kawabe, R, Iono, D, Nakanishi, K, Lee, M, Makiya, R

    ArXiv e-prints arXiv:1601.00195 2016年

  88. Properties of the Interstellar Medium in Star-Forming Galaxies at z ~ 1.4 Revealed with ALMA 査読有り

    Astrophys.J 89 812 2016年

  89. The Subaru FMOS Galaxy Redshift Survey (FastSound). III. The mass-metallicity relation and the fundamental metallicity relation at z˜1.4 査読有り

    Yabe, K, Ohta, K, Akiyama, M

    Publications of the Astronomical Society of Japan 67 (6) 102-16pp 2015年12月

    出版者・発行元:None

    DOI: 10.1093/pasj/psv079  

    ISSN:0004-6264

    eISSN:2053-051X

  90. The Subaru-XMM-Newton Deep Survey (SXDS). VIII. Multi-wavelength identification, optical/NIR spectroscopic properties, and photometric redshifts of X-ray sources 査読有り

    Masayuki Akiyama, Yoshihiro Ueda, Mike G. Watson, Hisanori Furusawa, Tadafumi Takata, Chris Simpson, Tomoki Morokuma, Toru Yamada, Kouji Ohta, Fumihide Iwamuro, Kiyoto Yabe, Naoyuki Tamura, Yuuki Moritani, Naruhisa Takato, Masahiko Kimura, Toshinori Maihara, Gavin Dalton, Ian Lewis, Hanshin Lee, Emma Curtis-Lake, Edward Macaulay, Frazer Clarke, John D. Silverman, Scott Croom, Masami Ouchi, Hitoshi Hanami, Jorge Diaz Tello, Tomohiro Yoshikawa, Naofumi Fujishiro, Kazuhiro Sekiguchi

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 67 (5) 82 2015年10月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psv050  

    ISSN:0004-6264

    eISSN:2053-051X

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    We report on the multi-wavelength identification of the X-ray sources found in the Subaru-XMM-Newton Deep Survey (SXDS) using deep imaging data covering the wavelength range between the far-UV and mid-IR (MIR). We select a primary counterpart of each X-ray source by applying the likelihood ratio method to R-band, 3.6 mu m, near-UV, and 24 mu m source catalogs as well as matching catalogs of active galactic nucleus (AGN) candidates selected in 1.4 GHz radio and i'-band variability surveys. Once candidates for Galactic stars, ultra-luminous X-ray sources in a nearby galaxy, and clusters of galaxies are removed there are 896 AGN candidates in the sample. We conduct spectroscopic observations of the primary counterparts with multi-object spectrographs in the optical and NIR; 65% of the X-ray AGN candidates are spectroscopically identified. For the remaining X-ray AGN candidates, we evaluate their photometric redshift with photometric data in 15 bands. Utilizing the multi-wavelength photometric data of the large sample of X-ray-selected AGNs, we evaluate the stellar masses, M-*, of the host galaxies of the narrow-line AGNs. The distribution of the stellarmass is remarkably constant from z=0.1 to 4.0. The relation between M-* and 2-10 keV luminosity can be explained with strong cosmological evolution of the relationship between the black hole mass and M-*. We also evaluate the scatter of the UV-MIR spectral energy distribution (SED) of the X-ray AGNs as a function of X-ray luminosity and absorption by the nucleus. The scatter is compared with galaxies which have redshift and stellarmass distributionmatched with the X-ray AGN. The UV-NIR (near-IR) SEDs of obscured X-ray AGNs are similar to those of the galaxies in the matched sample. In the NIR-MIR range, the median SEDs of X-ray AGNs are redder, but the scatter of the SEDs of the X-ray AGN broadly overlaps that of the galaxies in the matched sample.

  91. The Subaru FMOS galaxy redshift survey (FastSound). I. Overview of the survey targeting Hα emitters at z~1.4 査読有り

    Tonegawa, Motonari, Totani, Tomonori, Okada, Hiroyuki, Akiyama, Masayuki, Dalton, Gavin, Glazebrook, Karl, Iwamuro, Fumihide, Maihara, Toshinori, Ohta, Kouji, Shimizu, Ikkoh, al

    Publication of Astronomical Society of Japan 67 (5) 81 2015年10月

    出版者・発行元:None

    DOI: 10.1093/pasj/psv044  

    ISSN:0004-6264

    eISSN:2053-051X

  92. RAVEN AND THE CENTER OF MAFFEI 1: MULTI-OBJECT ADAPTIVE OPTICS OBSERVATIONS OF THE CENTER OF A NEARBY ELLIPTICAL GALAXY AND THE DETECTION OF AN INTERMEDIATE AGE POPULATION 査読有り

    T. J. Davidge, D. R. Andersen, O. Lardiere, C. Bradley, C. Blain, S. Oya, M. Akiyama, Y. H. Ono

    ASTROPHYSICAL JOURNAL 811 (2) 133 2015年10月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/811/2/133  

    ISSN:0004-637X

    eISSN:1538-4357

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    Near-infrared (NIR) spectra that have an angular resolution of similar to 0.15 arcsec are used to examine the stellar content of the central regions of the nearby elliptical galaxy Maffei 1. The spectra were recorded at the Subaru Telescope, with wavefront distortions corrected by the RAVEN Multi-object Adaptive Optics science demonstrator. The Ballick-Ramsey C-2 absorption bandhead near 1.76 mu m is detected, and models in which similar to 10%-20% of the light near 1.8 mu m originates from stars of spectral type C5 reproduce the depth of this feature. Archival NIR and mid-infrared images are also used to probe the structural and photometric properties of the galaxy. Comparisons with models suggest that an intermediate age population dominates the spectral energy distribution between 1 and 5 mu m near the galaxy center. This is consistent not only with the presence of C stars, but also with the large H beta index that has been measured previously for Maffei 1. The J - K color is more or less constant within 15 arcsec of the galaxy center, suggesting that the brightest red stars are well-mixed in this area.

  93. OPTICAL-INFRARED PROPERTIES OF FAINT 1.3mm SOURCES DETECTED WITH ALMA 査読有り

    Bunyo Hatsukade, Kouji Ohta, Kiyoto Yabe, Akifumi Seko, Ryu Makiya, Masayuki Akiyama

    ASTROPHYSICAL JOURNAL 810 (2) 91 2015年9月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/810/2/91  

    ISSN:0004-637X

    eISSN:1538-4357

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    We report optical-infrared (IR) properties of faint 1.3 mm sources (S-1.3mm = 0.2-1.0 mJy) detected with the Atacama Large Millimeter/submillimeter Array (ALMA) in the Subaru/XMM-Newton Deep Survey field. We searched for optical/IR counterparts of eight ALMA-detected sources (>= 4.0 sigma, the sum of the probability of spurious source contamination is similar to 1) in a K-band source catalog. Four ALMA sources have K-band counterpart candidates within a 0 ''.4 radius. Comparison between ALMA-detected and undetected K-band sources in the same observing fields shows that ALMA-detected sources tend to be brighter, more massive, and more actively forming stars. While many of the ALMA-identified submillimeter-bright galaxies (SMGs) in previous studies lie above the sequence of star-forming galaxies in the stellar mass-star formation rate plane, our ALMA sources are located in the sequence, suggesting that the ALMA-detected faint sources are more like " normal" star-forming galaxies rather than "classical" SMGs. We found a region where multiple ALMA sources and K-band sources reside in a narrow photometric redshift range (z similar to 1.3-1.6) within a radius of 5 '' (42 kpc if we assume z = 1.45). This is possibly a pre-merging system and we may be witnessing the early phase of formation of a massive elliptical galaxy.

  94. THE QUASAR-LBG TWO-POINT ANGULAR CROSS-CORRELATION FUNCTION AT z similar to 4 IN THE COSMOS FIELD 査読有り

    H. Ikeda, T. Nagao, Y. Taniguchi, K. Matsuoka, M. Kajisawa, M. Akiyama, T. Miyaji, N. Kashikawa, T. Morokuma, Y. Shioya, M. Enoki, P. Capak, A. M. Koekemoer, D. Masters, M. Salvato, D. B. Sanders, E. Schinnerer, N. Z. Scoville

    ASTROPHYSICAL JOURNAL 809 (2) 138 2015年8月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/809/2/138  

    ISSN:0004-637X

    eISSN:1538-4357

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    In order to investigate the origin of quasars, we estimate the bias factor for low-luminosity quasars at high redshift for the first time. In this study, we use the two-point angular cross-correlation function (CCF) for both low-luminosity quasars at -24 &lt; M-1450 &lt; -22 and Lyman-break galaxies (LBGs). Our sample consists of both 25 low-luminosity quasars (16 objects are spectroscopically confirmed low-luminosity quasars) in the redshift range 3.1 &lt; z &lt; 4.5 and 835 color-selected LBGs with z(LBG) ' &lt; 25.0 at z similar to 4 in the COSMOS field. We have performed our analysis for the following two quasar samples: (1) the spectroscopic sample (the 16 quasars confirmed by spectroscopy), and (2) the total sample (the 25 quasars including 9 quasars with photometric redshifts). The bias factor for low-luminosity quasars at z similar to 4 is derived by utilizing the quasar-LBG CCF and the LBG auto-correlation function. We then obtain the 86% upper limits of the bias factors for low-luminosity quasars, which are 5.63 and 10.50 for the total and the spectroscopic samples, respectively. These bias factors correspond to the typical dark matter halo masses, log(M-DM/ h(-1)M(circle dot))) = 12.7 and 13.5, respectively. This result is not inconsistent with the predicted bias for quasars that is estimated by the major merger models.

  95. FIELD: Automated emission line detection software for Subaru/FMOS near-infrared spectroscopy 査読有り

    Motonari Tonegawa, Tomonori Totani, Fumihide Iwamuro, Masayuki Akiyama, Gavin Dalton, Karl Glazebrook, Kouji Ohta, Hiroyuki Okada, Kiyoto Yabe

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 67 (3) 31 2015年6月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/psu127  

    ISSN:0004-6264

    eISSN:2053-051X

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    We describe the development of automated emission line detection software for the Fiber Multi-Object Spectrograph (FMOS), which is a near-infrared spectrograph fed by 400 fibers from the 0.2 deg(2) prime focus field of view of the Subaru Telescope. The software, FIELD (FMOS software for Image-based Emission Line Detection), is developed and tested mainly for the FastSound survey, which is targeting Ha emitting galaxies at z similar to 1.3 to measure the redshift space distortion as a test of general relativity beyond z similar to 1. The basic algorithm is to calculate the line signal-to-noise ratio (S/N) along the wavelength direction, given by a 2D convolution of the spectral image and a detection kernel representing a typical emission line profile. A unique feature of FMOS is its use of OH airglow suppression masks, requiring the use of flat-field images to suppress noise around the mask regions. Bad pixels on the detectors and pixels affected by cosmic rays are efficiently removed using the information obtained from the FMOS analysis pipeline. We limit the range of acceptable line-shape parameters for the detected candidates to further improve the reliability of line detection. The final performance of line detection is tested using a subset of the FastSound data; the false detection rate of spurious objects is examined by using inverted frames obtained by exchanging object and sky frames. The false detection rate is < 1% at S/N > 5, allowing an efficient and objective emission line search for FMOS data at the line flux level of greater than or similar to 1.0 x 10(-16) erg cm(-2) s(-1).

  96. Thirty Meter Telescope Detailed Science Case: 2015 査読有り

    Warren Skidmore, Ian Dell'Antonio, Misato Fukugawa, Aruna Goswami, Lei Hao, David Jewitt, Greg Laughlin, Charles Steidel, Paul Hickson, Luc Simard, Matthias Schöck, Tommaso Treu, Judith Cohen, G. C. Anupama, Mark Dickinson, Fiona Harrison, Tadayuki Kodama, Jessica R. Lu, Bruce Macintosh, Matt Malkan, Shude Mao, Norio Narita, Tomohiko Sekiguchi, Annapurni Subramaniam, Masaomi Tanaka, Feng Tian, Michael A'Hearn, Masayuki Akiyama, Babar Ali, Wako Aoki, Manjari Bagchi, Aaron Barth, Varun Bhalerao, Marusa Bradac, James Bullock, Adam J. Burgasser, Scott Chapman, Ranga-Ram Chary, Masashi Chiba, Michael Cooper, Asantha Cooray, Ian Crossfield, Thayne Currie, Mousumi Das, G. C. Dewangan, Richard de Grijs, Tuan Do, Subo Dong, Jarah Evslin, Taotao Fang, Xuan Fang, Christopher Fassnacht, Leigh Fletcher, Eric Gaidos, Roy Gal, Andrea Ghez, Mauro Giavalisco, Carol A. Grady, Thomas Greathouse, Rupjyoti Gogoi, Puragra Guhathakurta, Luis Ho, Priya Hasan, Gregory J. Herczeg, Mitsuhiko Honda, Masa Imanishi, Hanae Inami, Masanori Iye, Jason Kalirai, U. S. Kamath, Stephen Kane, Nobunari Kashikawa, Mansi Kasliwal, Vishal Kasliwal, Evan Kirby, Quinn M. Konopacky, Sebastien Lepine, Di Li, Jianyang Li, Junjun Liu, Michael C. Liu, Enrigue Lopez-Rodriguez, Jennifer Lotz, Philip Lubin, Lucas Macri, Keiichi Maeda, Franck Marchis, Christian Marois, Alan Marscher, Crystal Martin, Taro Matsuo, Claire Max, Alan McConnachie, Stacy McGough, Carl Melis, Leo Meyer, Michael Mumma, Takayuki Muto, Tohru Nagao, Joan R. Najita, Julio Navarro, Michael Pierce, Jason X. Prochaska, Masamune Oguri, Devendra K. Ojha, Yoshiko K. Okamoto, Glenn Orton, Angel Otarola, Masami Ouchi, Chris Packham, Deborah L. Padgett, Shashi Bhushan Pandey, Catherine Pilachowsky, Klaus M. Pontoppidan, Joel Primack, Shalima Puthiyaveettil, Enrico Ramirez-Ruiz, Naveen Reddy, Michael Rich, Matthew J. Richter, James Schombert, Anjan Ananda Sen, Jianrong Shi, Kartik Sheth, R. Srianand, Jonathan C. Tan, Masayuki Tanaka, Angelle Tanner, Nozomu Tominaga, David Tytler, Vivian U, Lingzhi Wang, Xiaofeng Wang, Yiping Wang, Gillian Wilson, Shelley Wright, Chao Wu, Xufeng Wu, Renxin Xu, Toru Yamada, Bin Yang, Gongbo Zhao, Hongsheng Zhao

    2015年5月5日

    DOI: 10.1088/1674-4527/15/12/001  

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    The TMT Detailed Science Case describes the transformational science that the Thirty Meter Telescope will enable. Planned to begin science operations in 2024, TMT will open up opportunities for revolutionary discoveries in essentially every field of astronomy, astrophysics and cosmology, seeing much fainter objects much more clearly than existing telescopes. Per this capability, TMT's science agenda fills all of space and time, from nearby comets and asteroids, to exoplanets, to the most distant galaxies, and all the way back to the very first sources of light in the Universe. More than 150 astronomers from within the TMT partnership and beyond offered input in compiling the new 2015 Detailed Science Case. The contributing astronomers represent the entire TMT partnership, including the California Institute of Technology (Caltech), the Indian Institute of Astrophysics (IIA), the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC), the National Astronomical Observatory of Japan (NAOJ), the University of California, the Association of Canadian Universities for Research in Astronomy (ACURA) and US associate partner, the Association of Universities for Research in Astronomy (AURA).

  97. FROM DIVERSITY TO DICHOTOMY, AND QUENCHING: MILKY-WAY-LIKE AND MASSIVE-GALAXY PROGENITORS AT 0.5 < z < 3.0 査読有り

    Takahiro Morishita, Takashi Ichikawa, Masafumi Noguchi, Masayuki Akiyama, Shannon G. Patel, Masaru Kajisawa, Tomokazu Obata

    ASTROPHYSICAL JOURNAL 805 (1) 34 2015年5月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/805/1/34  

    ISSN:0004-637X

    eISSN:1538-4357

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    Using the Hubble Space Telescope (HST)/WFC3 and Advanced Camera for Surveys multi-band imaging data taken in CANDELS and 3D-HST, we study the general properties and diversity of the progenitors of the Milky Way (MWs) and local massive galaxy (MGs) at 0.5 < z < 3.0, based on a constant cumulative number density analysis. After careful data reduction and stacking analysis, we conduct a radially resolved pixel spectral energy distribution fitting to obtain the radial distributions of the stellar mass and rest-frame colors. The stellar mass of MWs increases in a self-similar way, irrespective of the radial distance, while that of MGs grows in an inside-out way where they obtain similar to 75% of the total mass at the outer (>2.5 kpc) radius since z similar to 2. Although the radial mass profiles evolve in distinct ways, the formation and quenching of the central dense region (or bulge) ahead of the formation of the outer disk are found to be common for both systems. The sudden reddening of the bulge at z similar to 1.6 and z similar to 2.4 for MWs and MGs, respectively, suggests the formation of the bulge and would give a clue to the different gas accretion histories and quenching. A new approach to evaluate the morphological diversity is conducted by using the average surface density profile and its dispersion. The variety of the radial mass profiles for MGs peaks at higher redshift (z > 2.8) and then rapidly converges to a more uniform shape at z < 1.5, while that for MWs remains in the outer region over the redshift. Compared with the observed star-formation rates and color profiles, the evolution of variety is consistently explained by the star-formation activities.

  98. DETAILED SHAPE AND EVOLUTIONARY BEHAVIOR OF THE X-RAY LUMINOSITY FUNCTION OF ACTIVE GALACTIC NUCLEI 査読有り

    T. Miyaji, G. Hasinger, M. Salvato, M. Brusa, N. Cappelluti, F. Civano, S. Puccetti, M. Elvis, H. Brunner, S. Fotopoulou, Y. Ueda, R. E. Griffiths, A. M. Koekemoer, M. Akiyama, A. Comastri, R. Gilli, G. Lanzuisi, A. Merloni, C. Vignali

    ASTROPHYSICAL JOURNAL 804 (2) 104 2015年5月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/804/2/104  

    ISSN:0004-637X

    eISSN:1538-4357

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    We construct the rest-frame 2-10 keV intrinsic X-ray luminosity function (XLF) of active galactic nuclei (AGNs) from a combination of X-ray surveys from the all-sky Swift BAT survey to the Chandra Deep Field. South. We use similar to 3200 AGNs in our analysis, which covers six orders of magnitude in flux. The inclusion of XMM and Chandra COSMOS data has allowed us to investigate the detailed behavior of the XLF and evolution. In deriving our XLF, we take into account realistic AGN spectrum templates, absorption corrections, and probability. density distributions in photometric redshift. We present an analytical expression for the overall behavior of the XLF in terms of the luminosity-dependent density evolution, smoothed two-power-law expressions in 11 redshift shells, three-segment power-law expression of the number density evolution in four luminosity classes, and binned XLF. We observe a sudden flattening of the low luminosity end slope of the XLF slope at z greater than or similar to 0.6. Detailed structures of the AGN downsizing have also been revealed, where the number density curves have two clear breaks at all luminosity classes above log L-X &gt; 43. The two-break structure is suggestive of two-phase AGN evolution, consisting of major merger triggering and secular processes.

  99. THE GAS INFLOW AND OUTFLOW RATE IN STAR-FORMING GALAXIES AT z similar to 1.4 査読有り

    Kiyoto Yabe, Kouji Ohta, Masayuki Akiyama, Fumihide Iwamuro, Naoyuki Tamura, Suraphong Yuma, Gavin Dalton, Ian Lewis

    ASTROPHYSICAL JOURNAL 798 (1) 45 2015年1月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/798/1/45  

    ISSN:0004-637X

    eISSN:1538-4357

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    We try to constrain the gas inflow and outflow rate of star-forming galaxies at z similar to 1.4 by employing a simple analytic model for the chemical evolution of galaxies. The sample is constructed based on a large near-infrared spectroscopic sample observed with SubarulFMOS. The gas-phase metallicity is measured from the [N II] lambda 6584/H alpha emission line ratio and the gas mass is derived from the extinction corrected H alpha luminosity by assuming the Kennicutt Schmidt law. We constrain the inflow and outflow rate from the least-chi(2) fittings of the observed gasmass fraction, stellar mass, and metallicity with the analytic model. The joint chi(2) fitting shows that the best-fit inflow rate is similar to 1.8 and the outflow rate is similar to 0.6 in units of star-formation rate. By applying the same analysis to the previous studies at z similar to 0 and z similar to 2.2, it is shown that both the inflow and outflow rates decrease with decreasing redshift, which implies the higher activity of gas flow process at higher redshift. The decreasing trend of the inflow rate from z similar to 2.2 to z similar to 0 agrees with that seen in previous observational works with different methods, though the absolute value is generally larger than in previous works. The outflow rate and its evolution from z similar to 2.2 to z similar to 0 obtained in this work agree well with the independent estimations in previous observational works.

  100. TOWARD THE STANDARD POPULATION SYNTHESIS MODEL OF THE X-RAY BACKGROUND: EVOLUTION OF X-RAY LUMINOSITY AND ABSORPTION FUNCTIONS OF ACTIVE GALACTIC NUCLEI INCLUDING COMPTON-THICK POPULATIONS 査読有り

    Yoshihiro Ueda, Masayuki Akiyama, Guenther Hasinger, Takamitsu Miyaji, Michael G. Watson

    ASTROPHYSICAL JOURNAL 786 (2) 104 2014年5月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/786/2/104  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present the most up to date X-ray luminosity function (XLF) and absorption function of active galactic nuclei (AGNs) over the redshift range from 0 to 5, utilizing the largest, highly complete sample ever available obtained from surveys performed with Swift/BAT, MAXI, ASCA, XMM-Newton, Chandra, and ROSAT. The combined sample, including that of the Subaru/XMM-Newton Deep Survey, consists of 4039 detections in the soft (0.5-2 keV) and/or hard (>2 keV) band. We utilize a maximum likelihood method to reproduce the count rate versus redshift distribution for each survey, by taking into account the evolution of the absorbed fraction, the contribution from Compton-thick (CTK) AGNs, and broadband spectra of AGNs, including reflection components from tori based on the luminosity-and redshift-dependent unified scheme. We find that the shape of the XLF at z similar to 1-3 is significantly different from that in the local universe, for which the luminosity-dependent density evolution model gives much better description than the luminosity and density evolution model. These results establish the standard population synthesis model of the X-ray background (XRB), which well reproduces the source counts, the observed fractions of CTK AGNs, and the spectrum of the hard XRB. The number ratio of CTK AGNs to the absorbed Compton-thin (CTN) AGNs is constrained to be approximate to 0.5-1.6 to produce the 20-50 keV XRB intensity within present uncertainties, by assuming that they follow the same evolution as CTN AGNs. The growth history of supermassive black holes is discussed based on the new AGN bolometric luminosity function.

  101. A study of selection methods for Halpha-emitting galaxies at z ˜ 1.3 for the Subaru/FMOS galaxy redshift survey for cosmology (FastSound) 査読有り

    Tonegawa, M, Totani, T, Akiyama, M

    Publication of Astronomical Society of Japan 66 (2) 43 2014年4月

    出版者・発行元:None

    DOI: 10.1093/pasj/psu022  

    ISSN:0004-6264

    eISSN:2053-051X

  102. The mass-metallicity relation at z ˜ 1.4 revealed with Subaru/FMOS 査読有り

    Yabe, K, Ohta, K, Iwamuro, F, Akiyama, M

    MNRAS 437 (4) 3647-3663 2014年2月

    出版者・発行元:None

    DOI: 10.1093/mnras/stt2185  

    ISSN:0035-8711

    eISSN:1365-2966

  103. Multi-Object Adaptive Optics On-sky Results with RAVEN

    Olivier Lardiere, Dave Andersen, Cellia Blian, Colin Bradley, Darryl Gamroth, Kate Jackson, Przemek Lach, Reston Nash, Kim Venn, Jean-Pierre Veran, Carlos Correia, Shin Oya, Yutaka Hayano, Hiroshi Terada, Yoshito Ono, Masayuki Akiyama

    ADAPTIVE OPTICS SYSTEMS IV 9148 2014年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2055480  

    ISSN:0277-786X

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    Raven is a Multi Object Adaptive Optics (MOAO) technical and science demonstrator which had its first light at the Subaru telescope on May 13-14, 2014. Raven was built and tested at the University of Victoria AO Lab before shipping to Hawai`i. Raven includes three open loop wavefront sensors (WFSs), a central laser guide star WFS, and two independent science channels feeding light to the Subaru IRCS spectrograph. Raven supports different kinds of AO correction: SCAO, open-loop GLAO and MOAO. The MOAO mode can use different tomographic reconstructors, such as Learn-&-Apply or a model-based reconstructor. This paper presents the latest results obtained in the lab, which are consistent with simulated performance, as well as preliminary on-sky results, including echelle spectra from IRCS. Ensquared energy obtained on sky in 140mas slit is 17%, 30% and 41% for GLAO, MOAO and SCAO respectively. This result confirms that MOAO can provide a level of correction in between GLAO and SCAO, in any direction of the field of regard, regardless of the science target brightness.

  104. ULTIMATE-SUBARU: project status 査読有り

    Yutaka Hayano, Masayuki Akiyama, Takashi Hattori, Ikuru Iwata, Tadayuki Kodama, Olivier Lai, Yosuke Minowa, Yoshito Ono, Shin Oya, Koki Takiura, Ichi Tanaka, Yoko Tanaka, Nobuo Arimito

    ADAPTIVE OPTICS SYSTEMS IV 9148 2014年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2055042  

    ISSN:0277-786X

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    The project, "ULTIMATE-SUBARU", stands for "Ultra-wide Laser Tomographic Imager and MOS with AO for Transcendent Exploration at SUBARU Telescope." ULTIMATE-SUBARU provides a wide-field near infrared instrument at Cassegrain focus with GLAO. Performance simulation of GLAO at Subaru Telescope indicates that uniform PSFs can be obtained across the field of view up to 20 arcmin in diameter. This paper describes a current status of ULTIMATE-SUBARU project, science objectives, performance simulation update, system overview, feasibility of adaptive secondary mirror, and laser system.

  105. ULTIMATE-SUBARU: simulation update 査読有り

    Shin Oya, Yutaka Hayano, Olivier Lai, Ikuru Iwata, Tadayuki Kodama, Nobuo Arimoto, Yosuke Minowa, Masayuki Akiyama, Yoshito H. Ono, Hiroshi Terada, Tomonori Usuda, Hideki Takami, Testuo Nishimura, Naruhisa Takato, Daigo Tomono

    ADAPTIVE OPTICS SYSTEMS IV 9148 2014年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2055701  

    ISSN:0277-786X

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    A future plan for the next-generation Subaru adaptive optics, is a system based on an adaptive secondary mirror. A ground-layer adaptive optics combined with a new wide-field multi-object infrared camera and spectrograph will be a main application of the adaptive secondary mirror. A preliminary simulation results show that the resolution achieved by the ground-layer adaptive optics is expected to be better than 0.2 arcsecond in the K-band over 15 arcminutes field-of-view. In this paper, the performance simulation is updated taking dependence on observation conditions, the zenith angle and the season, into account.

  106. TMT-AGE: wide field of regard multi-object adaptive optics for TMT

    Masayuki Akiyama, Shin Oya, Yoshito H. Ono, Hideki Takami, Shinobu Ozaki, Yutaka Hayano, Ikuru Iwata, Kazuhiro Hane, Tong Wu, Tomoyasu Yamamuro, Yuji Ikeda

    ADAPTIVE OPTICS SYSTEMS IV 9148 (1) 14 2014年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2056320  

    ISSN:0277-786X

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    We introduce current status of the feasibility study on a wide field of regard (FoR) Multi-Object Adaptive Optics (MOAO) system for TMT (TMT-AGE: TMT-Analyzer for Galaxies in the Early universe). MOAO is a system which realize high spatial-resolution observations of multiple objects scattered in a wide FoR. In this study, we put emphasise on the FoR as wide as 10' diameter. The wide FoR is crucial to effectively observe very high-redshift galaxies, which have low surface number density. Simulations of an MOAO system with 8 LGSs show close-to-diffraction-limited correction can be achieved within 5' diameter FoR and moderate AO correction can be achieved within 10' diameter FoR. We discuss overall system design of the wide FoR MOAO system considering the constraint from the stroke of small-size deformable mirror (DM). We also introduce current status of developments of key components of an MOAO system; high-dynamic range wavefront sensor (WFS) and large-stroke small-size DM, and real time computer (RTC) with fast tomographic reconstruction.

  107. TMT-AGE: numerical simulation of a new tomographic reconstruction method for wide FoR MOAO

    Yoshito H. Ono, Akiyama Masayuki, Shin Oya

    ADAPTIVE OPTICS SYSTEMS IV 9148 (1) 6 2014年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2055912  

    ISSN:0277-786X

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    We are conducting a concept study on a wide field of regard (FoR) Multi-Object Adaptive Optics (MOAO) system for Thirty Meter Telescope (TMT-AGE: TMT-Analyzer for Galaxies in the Early universe). The main science target of TMT-AGE is high-redshift galaxies. Considering the small number density of high-redshift galaxies, enlarging the FoR of an MOAO system up to around 10' is critical. In order to increase the FoR of an MOAO system, we propose a new tomographic reconstruction method. In the new method, we use atmospheric wind profiles and WFS measurements at previous time steps to increase the number of virtual measurement points of atmospheric turbulence layers for tomographic reconstruction. We present the results of numerical simulations with the new tomography method. The simulations show the new method can reduce the tomographic error in a wide FoR.

  108. Large-scale membrane transfer process: its application to single-crystal-silicon continuous membrane deformable mirror

    Tong Wu, Takashi Sasaki, Masayuki Akiyama, Kazuhiro Hane

    JOURNAL OF MICROMECHANICS AND MICROENGINEERING 23 (12) 2013年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0960-1317/23/12/125003  

    ISSN:0960-1317

    eISSN:1361-6439

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    This paper describes a large-scale membrane transfer process developed for the construction of large-scale membrane devices via the transfer of continuous single-crystal-silicon membranes from one substrate to another. This technique is applied for fabricating a large stroke deformable mirror. A bimorph spring array is used to generate a large air gap between the mirror membrane and the electrode. A 1.9 mm x 1.9 mm x 2 mu m single-crystal-silicon membrane is successfully transferred to the electrode substrate by Au-Si eutectic bonding and the subsequent all-dry release process. This process provides an effective approach for transferring a free-standing large continuous single-crystal-silicon to a flexible suspension spring array with a large air gap.

  109. THE FORMATION OF THE MASSIVE GALAXIES IN THE SSA22 z=3.1 PROTOCLUSTER 査読有り

    M. Kubo, Y. K. Uchimoto, T. Yamada, M. Kajisawa, T. Ichikawa, Y. Matsuda, M. Akiyama, T. Hayashino, M. Konishi, T. Nishimura, K. Omata, R. Suzuki, I. Tanaka, T. Yoshikawa, D. M. Alexander, G. G. Fazio, J. -S. Huang, B. D. Lehmer

    ASTROPHYSICAL JOURNAL 778 (2) 170 2013年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/778/2/170  

    ISSN:0004-637X

    eISSN:1538-4357

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    We study the properties of K-band-selected galaxies (K-AB &lt; 24) in the z = 3.09 SSA22 protocluster field. 430 galaxies at 2.6 &lt; z(phot) &lt; 3.6 are selected as potential protocluster members in a 112 arcmin(2) area based on their photometric redshifts. We find that approximate to 20% of the massive galaxies with stellar masses &gt;10(11) M-circle dot at z(phot) similar to 3.1 have colors consistent with those of quiescent galaxies with ages &gt;0.5 Gyr. This fraction increases to approximate to 50% after correcting for unrelated foreground/background objects. We also find that 30% of the massive galaxies are heavily reddened, dusty, star-forming galaxies. Few such quiescent galaxies at similar redshifts are seen in typical survey fields. An excess surface density of 24 mu m sources at z(phot) similar to 3.1 is also observed, implying the presence of dusty star-formation activity in the protocluster. Cross-correlation with the X-ray data indicates that the fraction of K-band-selected protocluster galaxies hosting active galactic nuclei (AGNs) is also high compared with the field. The sky distribution of the quiescent galaxies, the 24 mu m sources, and the X-ray AGNs show clustering around a density peak of z = 3.1 Ly alpha emitters. A significant fraction of the massive galaxies have already become quiescent, while dusty star-formation is still active in the SSA22 protocluster. These findings indicate that we are witnessing the formation epoch of massive early-type galaxies in the centers of the predecessors to present-day rich galaxy clusters.

  110. FIRST SYSTEMATIC SEARCH FOR OXYGEN-LINE BLOBS AT HIGH REDSHIFT: UNCOVERING AGN FEEDBACK AND STAR FORMATION QUENCHING 査読有り

    Suraphong Yuma, Masami Ouchi, Alyssa B. Drake, Chris Simpson, Kazuhiro Shimasaku, Kimihiko Nakajima, Yoshiaki Ono, Rieko Momose, Masayuki Akiyama, Masao Mori, Masayuki Umemura

    ASTROPHYSICAL JOURNAL 779 (1) 53 2013年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/779/1/53  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present the first systematic search for extended metal-line [O II] lambda lambda 3726, 3729 nebulae, or [O II] blobs (O IIBs), at z = 1.2 using deep narrowband imaging with a survey volume of 1.9 x 10(5) Mpc(3) on the 0.62 deg(2) sky of Subaru-XMM Deep Survey (SXDS) field. We discover a giant O IIB, called "O IIB 1," with a spatial extent over similar to 75 kpc at a spectroscopic redshift of z = 1.18, and also identify a total of 12 O IIBs with a size of >30 kpc. Our optical spectrum of O IIB 1 presents [Ne v] lambda 3426 line at the 6 sigma level, indicating that this object harbors an obscured type-2 active galactic nucleus (AGN). The presence of gas outflows in this object is suggested by two marginal detections of Fe II lambda 2587 absorption and Fe II* lambda 2613 emission lines both of which are blueshifted at as large as 500-600 km s(-1), indicating that the heating source of O IIB 1 is AGN or associated shock excitation rather than supernovae produced by starbursts. The number density of O IIB 1-type giant blobs is estimated to be similar to 5 x 10(-6) Mpc(-3) at z similar to 1.2, which is comparable with that of AGNs driving outflow at a similar redshift, suggesting that giant O IIBs are produced only by AGN activity. On the other hand, the number density of small O IIBs, 6 x 10(-5) Mpc(-3), compared to that of z similar to 1 galaxies in the blue cloud in the same M-B range, may imply that 3% of star-forming galaxies at z similar to 1 are quenching star formation through outflows involving extended [O II] emission.

  111. THE COSMIC BPT DIAGRAM: CONFRONTING THEORY WITH OBSERVATIONS 査読有り

    Lisa J. Kewley, Christian Maier, Kiyoto Yabe, Kouji Ohta, Masayuki Akiyama, Michael A. Dopita, Tiantian Yuan

    ASTROPHYSICAL JOURNAL LETTERS 774 (1) 10 2013年9月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/2041-8205/774/1/L10  

    ISSN:2041-8205

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    We compare a large sample of galaxies between 0.5 < z < 2.6 with theoretical predictions for how the optical diagnostic line ratios in galaxy ensembles change as a function of cosmic time. We show that star-forming galaxies at high redshift (z > 1.5) are consistent with a model in which the interstellar medium conditions are more extreme at high redshift than seen in the global spectra of local galaxies. We speculate that global spectra of our high-redshift galaxies may be dominated by H II regions similar to the extreme clumpy, dense star-forming complexes in the Antennae and M82. The transition to local-type conditions occurs between 0.8 < z < 1.5. We conclude that classification schemes developed for local samples should not be applied at high redshift (z >= 1.5). We use our theoretical models to derive a new redshift-dependent classification line that utilizes the standard optical diagnostic line ratios [O III]/H beta and [N II]/H alpha. Our new line can be used to separate star-forming galaxies from active galactic nuclei (AGN) between z = 0 to z similar to 3.5. We anticipate that our redshift-dependent optical classification line will be useful for future large surveys with near-infrared multi-object spectrographs. We apply our classification line to a sample of gravitationally lensed galaxies at z similar to 2.5. Although limited by small numbers, we show that our classification line is consistent with the position of AGN that have been independently confirmed via other methods.

  112. A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys 査読有り

    M. Brightman, J. D. Silverman, V. Mainieri, Y. Ueda, M. Schramm, K. Matsuoka, T. Nagao, C. Steinhardt, J. Kartaltepe, D. B. Sanders, E. Treister, O. Shemmer, W. N. Brandt, M. Brusa, A. Comastri, L. C. Ho, G. Lanzuisi, E. Lusso, K. Nandra, M. Salvato, G. Zamorani, M. Akiyama, D. M. Alexander, A. Bongiorno, P. Capak, F. Civano, A. Del Moro, A. Doi, M. Elvis, G. Hasinger, E. S. Laird, D. Masters, M. Mignoli, K. Ohta, K. Schawinski, Y. Taniguchi

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 433 (3) 2485-2496 2013年8月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/mnras/stt920  

    ISSN:0035-8711

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    We present an investigation into how well the properties of the accretion flow on to a supermassive black hole may be coupled to those of the overlying hot corona. To do so, we specifically measure the characteristic spectral index, Gamma, of a power-law energy distribution, over an energy range of 2-10 keV, for X-ray selected, broad-lined radio-quiet active galactic nuclei (AGN) up to z similar to 2 in Cosmic Evolution Survey (COSMOS) and Extended Chandra Deep Field South (E-CDF-S). We test the previously reported dependence between Gamma and black hole mass, full width at half-maximum (FWHM) and Eddington ratio using a sample of AGN covering a broad range in these parameters based on both the Mg ii and H alpha emission lines with the later afforded by recent near-infrared spectroscopic observations using Subaru/Fibre Multi Object Spectrograph. We calculate the Eddington ratios, lambda(Edd), for sources where a bolometric luminosity (L-Bol) has been presented in the literature, based on spectral energy distribution fitting, or, for sources where these data do not exist, we calculate L-Bol using a bolometric correction to the X-ray luminosity, derived from a relationship between the bolometric correction and L-X/L-3000. From a sample of 69 X-ray bright sources (&gt; 250 counts), where Gamma can be measured with greatest precision, with an estimate of L-Bol, we find a statistically significant correlation between Gamma and lambda(Edd), which is highly significant with a chance probability of 6.59x 10(-8). A statistically significant correlation between Gamma and the FWHM of the optical lines is confirmed, but at lower significance than with lambda(Edd) indicating that lambda(Edd) is the key parameter driving conditions in the corona. Linear regression analysis reveals that Gamma = (0.32 +/- 0.05) log(10)lambda(Edd) + (2.27 +/- 0.06) and Gamma = (-0.69 +/- 0.11) log(10)(FWHM/km s(-1)) + (4.44 +/- 0.42). Our results on Gamma-lambda(Edd) are in very good agreement with previous results. While the Gamma-lambda(Edd) relationship means that X-ray spectroscopy may be used to estimate black hole accretion rate, considerable dispersion in the correlation does not make this viable for single sources, however could be valuable for large X-ray spectral samples, such as those to be produced by eROSITA.

  113. A COMPARATIVE ANALYSIS OF VIRIAL BLACK HOLE MASS ESTIMATES OF MODERATE-LUMINOSITY ACTIVE GALACTIC NUCLEI USING SUBARU/FMOS 査読有り

    K. Matsuoka, J. D. Silverman, M. Schramm, C. L. Steinhardt, T. Nagao, J. Kartaltepe, D. B. Sanders, E. Treisters, G. Hasinger, M. Akiyama, K. Ohta, Y. Ueda, A. Bongiorno, W. N. Brandt, M. Brusa, P. Capak, F. Civano, A. Comastri, M. Elvis, S. J. Lilly, V. Mainieri, D. Masters, M. Mignoli, M. Salvato, J. R. Trump, Y. Taniguchi, G. Zamorani, D. M. Alexander, K. Schawinski

    ASTROPHYSICAL JOURNAL 771 (1) 64 2013年7月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/771/1/64  

    ISSN:0004-637X

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    We present an analysis of broad emission lines observed in moderate-luminosity active galactic nuclei (AGNs), typical of those found in X-ray surveys of deep fields, with the goal of testing the validity of single-epoch virial black hole mass estimates. We have acquired near-infrared spectra of AGNs up to z similar to 1.8 in the COSMOS and Extended Chandra Deep Field-South Survey, with the Fiber Multi-Object Spectrograph mounted on the Subaru telescope. These near-infrared spectra provide a significant detection of the broad H alpha line, shown to be a reliable probe of black hole mass at low redshift. Our sample has existing optical spectroscopy that provides a detection of Mg II, typically used for black hole mass estimation at z greater than or similar to 1. We carry out a spectral-line fitting procedure using both H alpha and Mg II to determine the virial velocity of gas in the broad-line region, the continuum luminosity at 3000 angstrom, and the total H alpha line luminosity. With a sample of 43 AGNs spanning a range of two decades in luminosity, we find a tight correlation between the ultraviolet and emission-line luminosity. There is also a close one-to-one relationship between the full width at half-maximum of H alpha and Mg II. Both of these then lead to there being very good agreement between H alpha- and Mg II-based masses over a wide range in black hole mass, i.e., M-BH similar to 10(7-9) M-circle dot. In general, these results demonstrate that local scaling relations, using Mg II or H alpha, are applicable for AGNs at moderate luminosities and up to z similar to 2.

  114. FAINT END OF 1.3 mm NUMBER COUNTS REVEALED BY ALMA 査読有り

    Bunyo Hatsukade, Kouji Ohta, Akifumi Seko, Kiyoto Yabe, Masayuki Akiyama

    ASTROPHYSICAL JOURNAL LETTERS 769 (2) 27 2013年6月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/2041-8205/769/2/L27  

    ISSN:2041-8205

    eISSN:2041-8213

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    We present the faint end of number counts at 1.3 mm (238 GHz) obtained with the Atacama Large Millimeter/submillimeter Array (ALMA). Band 6 observations were carried out targeting 20 star-forming galaxies at z similar to 1.4 in the Subaru/XMM-Newton Deep Survey field. In the observations, we serendipitously detect 15 sources (>= 3.8 sigma, S-1.3 (mm) = 0.15-0.61 mJy) other than the targeted sources. We create number counts by using these "sub-mJy sources," which probe the faintest flux range among surveys at millimeter wavelengths. The number counts are consistent with (flux-scaled) number counts at 850 mu m and 870 mu m obtained with gravitational lensing clusters. The ALMA number counts agree well with model predictions, which suggest that these sub-mJy populations aremore like "normal" star-forming galaxies than "classical" submillimeter galaxies with intense star-forming activity. In this flux range, similar to 80% of the extragalactic background light at 1.3 mm is resolved into individual sources.

  115. A continuous single-crystal-silicon membrane deformable mirror using bimorph spring

    Tong Wu, Takashi Sasaki, Masayuki Akiyama, Kazuhiro Hane

    MEMS ADAPTIVE OPTICS VII 8617 2013年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.2002785  

    ISSN:0277-786X

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    We propose, design and fabricate here an electrostatically actuated continuous single-crystal-silicon membrane deformable mirror (DM) for astronomical observation. To get a large stroke, a bimorph spring array is used to generate a large air gap between the mirror membrane and the electrode. A DM with a 1.8mm x 1.8mm mirror membrane are fabricated by combining Au-Si eutectic wafer bonding and the subsequent all-dry release process. The stroke of the DM is 3.5 mu m at 115V. The influence function on the nearest neighbor is 51%. The fill factor of the DM is 99.9%.

  116. BLACK HOLE MASS AND EDDINGTON RATIO DISTRIBUTION FUNCTIONS OF X-RAY-SELECTED BROAD-LINE AGNs AT z similar to 1.4 IN THE SUBARU XMM-NEWTON DEEP FIELD 査読有り

    K. Nobuta, M. Akiyama, Y. Ueda, M. G. Watson, J. Silverman, K. Hiroi, K. Ohta, F. Iwamuro, K. Yabe, N. Tamura, Y. Moritani, M. Sumiyoshi, N. Takato, M. Kimura, T. Maihara, G. Dalton, I. Lewis, D. Bonfield, H. Lee, E. Curtis-Lake, E. Macaulay, F. Clarke, K. Sekiguchi, C. Simpson, S. Croom, M. Ouchi, H. Hanami, T. Yamada

    ASTROPHYSICAL JOURNAL 761 (2) 143 2012年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/761/2/143  

    ISSN:0004-637X

    eISSN:1538-4357

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    In order to investigate the growth of supermassive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line active galactic nuclei (AGNs) at z similar to 1.4 in the Subaru XMM-Newton Deep Survey (SXDS) field. A significant part of the accretion growth of SMBHs is thought to take place in this redshift range. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad Mg II line and 3000 angstrom monochromatic luminosity. We supplement the Mg II FWHM values with the H alpha FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMFs and ERDFs are calculated using the V-max method. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMFs and ERDFs by applying the maximum likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local universe, then the corrected BHMF at z = 1.4 has a higher number density above 10(8) M-circle dot but a lower number density below that mass range. The evolution may be indicative of a downsizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDFs from z = 1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rates close to the Eddington limit is higher at higher redshifts.

  117. FMOS near-IR spectroscopy of Herschel-selected galaxies: star formation rates, metallicity and dust attenuation at z ˜ 1 査読有り

    I. G. Roseboom, A. Bunker, M. Sumiyoshi, L. Wang, G. Dalton, M. Akiyama, J. Bock, D. Bonfield, V. Buat, C. Casey, E. Chapin, D. L. Clements, A. Conley, E. Curtis-Lake, A. Cooray, J. S. Dunlop, D. Farrah, S. J. Ham, E. Ibar, F. Iwamuro, M. Kimura, I. Lewis, E. Macaulay, G. Magdis, T. Maihara, G. Marsden, T. Mauch, Y. Moritani, K. Ohta, S. J. Oliver, M. J. Page, B. Schulz, Douglas Scott, M. Symeonidis, N. Takato, N. Tamura, T. Totani, K. Yabe, M. Zemcov

    MNRAS 426 (3) 1782-1792 2012年11月

    出版者・発行元:None

    DOI: 10.1111/j.1365-2966.2012.21777.x  

    ISSN:0035-8711

    eISSN:1365-2966

  118. COMOVING SPACE DENSITY AND OBSCURED FRACTION OF HIGH-REDSHIFT ACTIVE GALACTIC NUCLEI IN THE SUBARU/XMM-NEWTON DEEP SURVEY 査読有り

    Kazuo Hiroi, Yoshihiro Ueda, Masayuki Akiyama, Mike G. Watson

    ASTROPHYSICAL JOURNAL 758 (1) 49 2012年10月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/758/1/49  

    ISSN:0004-637X

    eISSN:1538-4357

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    We study the comoving space density of X-ray-selected luminous active galactic nuclei (AGNs) and the obscured AGN fraction at high redshifts (3 < z < 5) in the Subaru/XMM-Newton Deep Survey field. From an X-ray source catalog with high completeness of optical identification thanks to deep optical images, we select a sample of 30 AGNs at z > 3 with intrinsic (de-absorbed and rest-frame 2-10 keV) luminosities of L-X = 10(44-45) erg s(-1) detected in the 0.5-2 keV band, consisting of 20 and 10 objects with spectroscopic and photometric redshifts, respectively. Utilizing the 1/V-max method, we confirm that the comoving space density of luminous AGNs decreases with redshift above z > 3. When combined with the Chandra-COSMOS result of Civano et al., the density decline of AGNs with L-X = 10(44-45) erg s(-1) is well represented by a power law of (1 + z)(-6.2 +/- 0.9). We also determine the fraction of X-ray obscured AGNs with N-H > 10(22) cm(-2) in the Compton-thin population to be 0.54(-0.19)(+0.17), by carefully taking into account observational biases including the effects of photon statistics for each source. This result is consistent with an independent determination of the type-2 AGN fraction based on optical properties, for which the fraction is found to be 0.59 +/- 0.09. Comparing our result with that obtained in the local universe, we conclude that the obscured fraction of luminous AGNs increases significantly from z = 0 to z > 3 by a factor of 2.5 +/- 1.1.

  119. NIR Spectroscopy of Star-Forming Galaxies at z similar to 1.4 with Subaru/FMOS: The Mass-Metallicity Relation 査読有り

    Kiyoto Yabe, Kouji Ohta, Fumihide Iwamuro, Suraphong Yuma, Masayuki Akiyama, Naoyuki Tamura, Masahiko Kimura, Naruhisa Takato, Yuuki Moritani, Masanao Sumiyoshi, Toshinori Maihara, John Silverman, Gavin Dalton, Ian Lewis, David Bonfield, Hanshin Lee, Emma Curtis Lake, Edward Macaulay, Fraser Clarke

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 64 (3) 60 2012年6月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/64.3.60  

    ISSN:0004-6264

    eISSN:2053-051X

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    We present near-infrared spectroscopic observations of star-forming galaxies at z similar to 1.4 with FMOS on the Subaru Telescope. We observed K-band selected galaxies in the SXDS/UDS fields with K <= 23.9 mag, 1.2 <= z(ph) <= 1.6, M-* >= 10(9.5) M-circle dot, and expected F(H alpha) >= 10(-16) erg s(-1) cm(-2); 71 objects in the sample have significant detections of Ha. For these objects, excluding possible AGNs, identified from the BPT diagram, gas-phase metallicities were obtained from the [N II] / H alpha line ratio. The sample is split into three stellar-mass bins, and the spectra are stacked in each stellar-mass bin. The mass-metallicity relation obtained at z similar to 1.4 is located between those at z similar to 0.8 and z similar to 2.2. We constrain the intrinsic scatter to be similar to 0.1 dex, or larger in the mass-metallicity relation at z similar to 1.4; the scatter may be larger at higher redshifts. We found trends that the deviation from the mass-metallicity relation depends on the SFR (Star-formation rate) and the half light radius: Galaxies with higher SFR and larger half light radii show lower metallicities at a given stellar mass. One possible scenario for the trends is the infall of pristine gas accreted from IGM, or through merger events. Our data points show larger scatter than the fundamental metallicity relation (FMR) at z similar to 0.1, and the average metallicities slightly deviate from the FMR. The compilation of the mass-metallicity relations at z similar to 3 to z similar to 0.1 shows that they evolve smoothly from z similar to 3 to z similar to 0 without changing the shape so much, except for the massive part at z similar to 0.

  120. FIBRE-Pac: FMOS Image-Based Reduction Package 査読有り

    Fumihide Iwamuro, Yuuki Moritani, Kiyoto Yabe, Masanao Sumiyoshi, Kaori Kawate, Naoyuki Tamura, Masayuki Akiyama, Masahiko Kimura, Naruhisa Takato, Philip Tait, Kouji Ohta, Tomonori Totani, Yuji Suzuki, Motonari Tonegawa

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 64 (3) 59 2012年6月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/64.3.59  

    ISSN:0004-6264

    eISSN:2053-051X

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    The FIBRE-pac (FMOS image-based reduction package) is an IRAF-based reduction tool for the fiber multiple-object spectrograph (FMOS) of the Subaru telescope. To reduce FMOS images, a number of special techniques are necessary, because each image contains about 200 separate spectra with airglow emission lines variable in spatial and time domains, and with complicated throughput patterns for airglow masks. In spite of these features, almost all of the reduction processes, except for a few steps, are carried out automatically by scripts in text format, making it easy to check the commands step by step. Wavelength- and flux-calibrated images together with their noise maps are obtained using this reduction package.

  121. ASSEMBLY OF MASSIVE GALAXIES IN A HIGH-z PROTOCLUSTER 査読有り

    Yuka K. Uchimoto, Toru Yamada, Masaru Kajisawa, Mariko Kubo, Takashi Ichikawa, Yuichi Matsuda, Masayuki Akiyama, Tomoki Hayashino, Masahiro Konishi, Tetsuo Nishimura, Koji Omata, Ryuji Suzuki, Ichi Tanaka, Chihiro Tokoku, Tomohiro Yoshikawa

    ASTROPHYSICAL JOURNAL 750 (2) 116 2012年5月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/750/2/116  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present the results of wide-field deep JHK imaging of the SSA22 field using the MOIRCS instrument equipped with the Subaru telescope. The observed field is 112 arcmin(2) in area, which covers the z = 3.1 protocluster characterized by the overdensities of Ly alpha emitters (LAEs) and Ly alpha blobs (LABs). The 5 sigma limiting magnitude is K-AB = 24.3. We extract the potential protocluster members from the K-selected sample by using the multi-band photometric-redshift selection as well as the simple color cut for distant red galaxies (DRGs; J - K-AB > 1.4). The surface number density of DRGs in our observed fields shows clear excess compared with those in the blank fields, and the location of the densest area whose projected overdensity is twice the average coincides with the large-scale density peak of LAEs. We also found that K-band counterparts with z(phot) similar or equal to 3.1 are detected for 75% (15/20) of the LABs within their Ly alpha halo, and the 40% (8/20) of LABs have multiple components, which gives a direct evidence of the hierarchical multiple merging in galaxy formation. The stellar mass of LABs correlates with their luminosity, isophotal area, and the Ly alpha velocity widths, implying that the physical scale and the dynamical motion of Ly alpha emission are closely related to their previous star formation activities. Highly dust-obscured galaxies such as hyper extremely red objects (J - K-AB > 2.1) and plausible K-band counterparts of submillimeter sources are also populated in the high-density region.

  122. Radio imaging of the Subaru/XMM-Newton Deep Field- III. Evolution of the radio luminosity function beyond z=1 査読有り

    Chris Simpson, Steve Rawlings, Rob Ivison, Masayuki Akiyama, Omar Almaini, Emma Bradshaw, Scott Chapman, Rob Chuter, Scott Croom, Jim Dunlop, Sebastien Foucaud, Will Hartley

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 421 (4) 3060-3083 2012年4月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1111/j.1365-2966.2012.20529.x  

    ISSN:0035-8711

    eISSN:1365-2966

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    We present spectroscopic and 11-band photometric redshifts for galaxies in the 100-mu Jy Subaru/XMMNewtonDeep Field radio source sample. We find good agreement between our redshift distribution and that predicted by the Square Kilometre Array (SKA) Simulated Skies project. We find no correlation between K-band magnitude and radio flux, but show that sources with 1.4-GHz flux densities below similar to 1 mJy are fainter in the near-infrared than brighter radio sources at the same redshift, and we discuss the implications of this result for spectroscopically incomplete samples where the Kz relation has been used to estimate redshifts. We use the infraredradio correlation to separate our sample into radio-loud and radio-quiet objects and show that only radio-loud hosts have spectral energy distributions consistent with predominantly old stellar populations, although the fraction of objects displaying such properties is a decreasing function of radio luminosity. We calculate the 1.4-GHz radio luminosity function (RLF) in redshift bins to z= 4 and find that the space density of radio sources increases with lookback time to z approximate to 2, with a more rapid increase for more powerful sources. We demonstrate that radio-loud and radio-quiet sources of the same radio luminosity evolve very differently. Radio-quiet sources display strong evolution to z approximate to 2 while radio-loud active galactic nuclei below the break in the RLF evolve more modestly and show hints of a decline in their space density at z > 1, with this decline occurring later for lower-luminosity objects. If the radio luminosities of these sources are a function of their black hole spins then slowly rotating black holes must have a plentiful fuel supply for longer, perhaps because they have yet to encounter the major merger that will spin them up and use the remaining gas in a major burst of star formation.

  123. Behavior of Bacillus Bacteria in Coffee, Black Tea, and Green Tea Drinks

    Teruyuki Miyai, Masayuki Akiyama, Minoru Nakagawa, Yoichiro Yano, Michio Ikeda, Nobuo Ichihashi

    JOURNAL OF THE JAPANESE SOCIETY FOR FOOD SCIENCE AND TECHNOLOGY-NIPPON SHOKUHIN KAGAKU KOGAKU KAISHI 59 (11) 591-594 2012年

    出版者・発行元:JAPAN SOC FOOD SCIENCE TECHNOLOGY

    ISSN:1341-027X

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    The behavior of heat-resistant spore-forming bacteria (Bacillus cereths, B. subtilis, and B. coagulans) during storage in various coffee, black tea, and green tea drinks was investigated. Spores of each Bacillus species were inoculated into each drink. After heat pasteurization at the lowest condition under the Food Sanitation Act for soft drinks with >= pH 4.6 (85 degrees C, 30 min), viable bacterial counts under each optimum growth temperature were measured for two weeks. Viable counts of the three species of Bacillus inoculated into coffee. black tea, and green tea without milk decreased, whereas B. cereus and B. subtilis increased in coffee and black tea drink with milk. These results suggest that the commercial sterility of coffee, black tea, and green tea drinks without milk can be guaranteed with pasteurization of 85 degrees C for 30 min, even if the Bacillus species is present. (Received Mar. 30, 2012 : Accepted Jul. 23. 2012)

  124. MOAO test bench in Tohoku University

    Masayuki Akiyama, Yoshito Ono, Shin Oya, Kazuhiro Hane, Tong Wu

    ADAPTIVE OPTICS SYSTEMS III 8447 2012年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.925974  

    ISSN:0277-786X

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    We are conducting AO development activities in Tohoku university targeting Multi-Object Adaptive Optics (MAO) system for the next generation ground-based large telescopes. In order to evaluate the accuracy of the tomographic estimation, which is a key of an MOAO system, we assembled a test optical bench to simulate an MOAO system in our optical lab. The system consists with 1) four light sources with single-mode fibers simulating three guide stars and one target object, 2) multiple phase plates simulating atmospheric turbulence structure, and 3) 4 Shack-Hartmann wavefront sensors. Wavefront data from the sensors are reduced with the tomographic algorithm. The evaluation of the accuracy of the tomographic wavefront reconstruction is underway. Additionally, evaluation of an open-loop control of an AO system is underway using an independent module. Once the accuracy of the open-loop control is established, the module will be installed in the tomography test bench and the entire system will be evaluated as an MOAO system. In parallel, we are conducting a development of a large stroke (20pm) Micro Electro Mechanical Systems (MEN'S) deformable mirror with large number of elements (>3000). Current status of the development is described.

  125. A preliminary simulation result of the next-generation wide-field AO at Subaru Telescope 査読有り

    Shin Oya, Masayuki Akiyama, Yutaka Hayano, Yosuke Minowa, Ikuru Iwata, Hiroshi Terada, Tomonori Usuda, Hideki Takami, Testuo Nishimura, Tadayuki Kodama, Naruhisa Takato, Daigo Tomono, Yoshito Ono

    ADAPTIVE OPTICS SYSTEMS III 8447 2012年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.926556  

    ISSN:0277-786X

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    A wide-field adaptive optics system based on an adaptive secondary mirror (ASM) is one of a future plan for the next-generation Subaru adaptive optics system. The main application of ASM based AO will be a ground-layer adaptive optics (GLAO) with field-of-view larger than 10 arc minutes. The high Strehl-ratio of on-source correction by high-order ASM (expected to be about 1000) and the reduction of emissivity are also attractive points. In this paper, we report a preliminary result of simulations for the these applications of ASM to study conceptual design of the next-generation wide-field Subaru adaptive optics.

  126. MOIRCS Deep Survey. VII. NIR Morphologies of Star-Forming Galaxies at Redshift z similar to 1

    Masahiro Konishi, Masayuki Akiyama, Masaru Kajisawa, Takashi Ichikawa, Ryuji Suzuki, Chihiro Tokoku, Yuka Katsuno Uchimoto, Tomohiro Yoshikawa, Ichi Tanaka, Masato Onodera, Masami Ouchi, Koji Omata, Tetsuo Nishimura, Toru Yamada

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 63 S363-S377 2011年3月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/63.sp2.S363  

    ISSN:0004-6264

    eISSN:2053-051X

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    We investigated rest-frame near-infrared (NIR) morphologies of a sample of 139 galaxies with M-s >= 1 x 10(10) M-circle dot at z = 0.8-1.2 in the GOODS-North field using our deep NIR imaging data (MOIRCS Deep Survey, MODS). We focused on Luminous Infrared Galaxies (LIRGs), which dominate a high star formation rate (SFR) density at z similar to 1, in a sample identified by cross-correlating with the Spitzer/MIPS 24 mu m source catalog. We performed two-dimensional light profile fittings of z similar to 1 galaxies in the K-s-band (rest-frame J-band) with a single-component Sersic model. We found that at z similar to 1, similar to 90% of the LIRGs have low Sersic indices (n < 2.5, similar to disk-like galaxies) in the K-s-band, and that those disk-like LIRGs consist of similar to 60% of the whole disk-like sample above M-s >= 3 x 10(10) M-circle dot. The z similar to 1 disk-like LIRGs are comparable to or similar to 20% smaller at the maximum in size compared to local disk-like galaxies in the same stellar mass range. When we examined rest-frame UV-optical morphologies using the HST/ACS images, the rest-frame B-band sizes of the z similar to 1 disk-like galaxies were found to be comparable to those of the local disk-like galaxies, as reported by previous studies on the size evolution of disk-like galaxies in the rest-frame optical band. By measuring color gradients (galaxy sizes as a function of wavelength) of the z similar to 1 and local disk-like galaxies, we found that the z similar to 1 disk-like galaxies have a 3-5 times steeper color gradient than the local ones. Our results indicate that (i) more than a half of the relatively massive disk-like galaxies at z similar to 1 are in violent star-formation epochs observed as LIRGs, and also (ii) that most of those LIRGs are constructing their fundamental disk structure vigorously. The high SFR density in the universe at z similar to 1 may be dominated by such star formation in the disk region in massive galaxies.

  127. MOIRCS Deep Survey. X. Evolution of Quiescent Galaxies as a Function of Stellar Mass at 0.5 < z < 2.5 査読有り

    Masaru Kajisawa, Takashi Ichikawa, Tomohiro Yoshikawa, Toru Yamada, Masato Onodera, Masayuki Akiyama, Ichi Tanaka

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 63 S403-S414 2011年3月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/63.sp2.S403  

    ISSN:0004-6264

    eISSN:2053-051X

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    We studied the evolution of quiescent galaxies at 0.5 < z < 2.5 as a function of the stellar mass, using very deep NIR imaging data from the MOIRCS Deep Survey in the GOODS-North region. The deep NIR data allowed us to construct a stellar mass-limited sample of quiescent galaxies down to similar to 10(10) M-circle dot even at z similar to 2, for the first time. We selected quiescent galaxies with age /tau > 6 by performing a SED fitting of the multi broad-band photometry from the U to Spitzer 5.8 mu m bands with the population synthesis model of Bruzual and Chariot (2003, MNRAS, 344, 1000), where exponentially decaying star-formation histories are assumed. The number density of quiescent galaxies increases by a factor of similar to 3 from 1.0 < z < 1.5 to 0.5 < z < 1.0, and by a factor of similar to 10 from 1.5 < z < 2.5 to 0.5 < z < 1.0, while that of star-forming galaxies with age/tau < 4 increases only by factors of similar to 2 and similar to 3 in the same redshift ranges. At 0.5 < z < 2.5, the low-mass slope of the stellar mass function of quiescent galaxies is alpha similar to 0-0.6, which is significantly flatter than those of star-forming galaxies (alpha similar to -1.3--1.5). As a result, the fraction of quiescent galaxies in the overall galaxy population increases with stellar mass in the redshift range. The fraction of quiescent galaxies at 10(11)-10(11.5) M-circle dot increases from similar to 20%-30% at z similar to 2 to similar to 40%-60% at z similar to 0.75, while that at 10(10)-10(10.5) M-circle dot increases from less than or similar to 5% to similar to 15% in the same redshift range. These results could suggest that the quenching of star formation had been more effective in more massive galaxies at 1 less than or similar to z less than or similar to 2. Such a mass-dependent quenching could explain the rapid increase in the number density of similar to M* galaxies relative to lower-mass galaxies at z greater than or similar to 1-1.5.

  128. MOIRCS Deep Survey. IX. Deep Near-Infrared Imaging Data and Source Catalog 査読有り

    Masaru Kajisawa, Takashi Ichikawa, Ichi Tanaka, Toru Yamada, Masayuki Akiyama, Ryuji Suzuki, Chihiro Tokoku, Yuka Katsuno Uchimoto, Masahiro Konishi, Tomohiro Yoshikawa, Tetsuo Nishimura, Koji Omata, Masami Ouchi, Ikuru Iwata, Takashi Hamana, Masato Onddera

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 63 S379-S401 2011年3月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/63.sp2.S379  

    ISSN:0004-6264

    eISSN:2053-051X

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    We present deep J-, H-, and K-s-band imaging data of the MOIRCS Deep Survey (MODS), which was carried out with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) mounted on the Subaru Telescope in the GOODS-North region. The data reach 5 sigma total limiting magnitudes for point sources of J = 23.9, H = 22.8, and K-s = 22.8 (Vega magnitude) over 103 arcmin(2) (wide field). In 28 arcmin(2) of the survey area, which is an ultra-deep field of the MODS (deep field), the data reach 5 sigma depths of J = 24.8, H = 23.4, and K-s = 23.8. The spatial resolutions of the combined images are FWHM similar to 0.'' 6 and 0.'' 5 for the wide and deep fields in all bands, respectively. Combining the MODS data with the multi-wavelength public data taken with the HST, Spitzer, and other ground-based telescopes in the GOODS field, we constructed a multi-wavelength photometric catalog of K-s-selected sources. Using the catalog, we present K-s-band number counts and near-infrared color distribution of the detected objects; we also demonstrate some selection techniques with the NIR colors for high redshift galaxies. These data and catalog are publicly available via Internet.

  129. Lyman 'bump' galaxies - II. A possible signature of massive extremely metal-poor or metal-free stars in z= 3.1 Lyα emitters 査読有り

    A.K.Inoue, K.Kousai, I.Iwata, Y.Matsuda, E.Nakamura, M.Horie, T.Hayashino, C.Tapken, M.Akiyama

    Monthly Notices of the Royal Astronomical Society 411 (4) 2336-2352 2011年3月

    出版者・発行元:None

    DOI: 10.1111/j.1365-2966.2010.17851.x  

    ISSN:0035-8711

    eISSN:1365-2966

  130. THE MASS-DEPENDENT CLUSTERING HISTORY OF K-SELECTED GALAXIES AT z < 4 IN THE SXDS/UDS FIELD 査読有り

    Junko Furusawa, Kazuhiro Sekiguchi, Tadafumi Takata, Hisanori Furusawa, Kazuhiro Shimasaku, Chris Simpson, Masayuki Akiyama

    ASTROPHYSICAL JOURNAL 727 (2) 111 2011年2月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/727/2/111  

    ISSN:0004-637X

    eISSN:1538-4357

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    We investigate mass-dependent galaxy evolution based on a large sample of (more than 50,000) K-band selected galaxies in a multi-wavelength catalog of the Subaru/XMM-Newton Deep Survey and the UKIRT Infrared Deep Sky Survey/Ultra Deep Survey. We employ optical to near-infrared photometry to determine photometric redshifts of these galaxies. Then, we estimate the stellar mass of our sample galaxies using a standard fitting procedure as we used for estimation of the photometric redshift. From the sample galaxies, we obtain the stellar mass function of galaxies and the cosmic stellar mass density up to z similar to 4. Our results are consistent with previous studies and we find a considerable number of low-mass galaxies (M-* similar to 10(10.5)) at the redshift range 3 < z < 4. By combining stellar masses and spatial distributions of galaxies derived from a large number of galaxies in the contiguous wide and deep field, we examine properties of the mass-dependent clustering of galaxies. The correlation functions of our sample galaxies show clear evolution and they connect to that in the local universe consistently. Also, we find that the massive galaxies show strong clustering throughout our studied redshift range. The correlation length of massive galaxies rapidly decreases from z = 4 to 2. The mass of dark halos hosting the intermediate-mass value galaxies changes from high (10(14) M-circle dot) to low (10(13) M-circle dot) with decreasing redshift at around z similar to 2. We also find some high-mass density regions of massive galaxies at 1.4 <= z < 2.5 in our sample. These concentrations of massive galaxies may be candidate progenitors of the present-day clusters of galaxies. At this redshift range, massive star-forming galaxies are the dominant population making up the structures and the passively evolving galaxies show stronger clustering and they may have formed earlier than those star-forming galaxies.

  131. Statistics of 207 Lyα Emitters at a Redshift Near 7: Constraints on Reionization and Galaxy Formation Models 査読有り

    M.Ouchi, K.Shimasaku, H.Furusawa, T.Saito, M.Yoshida, M.Akiyama

    The Astrophysical Journal 723 (1) 869-894 2010年11月

    出版者・発行元:None

    DOI: 10.1088/0004-637X/723/1/869  

    ISSN:0004-637X

    eISSN:1538-4357

  132. MOIRCS DEEP SURVEY. VIII. EVOLUTION OF STAR FORMATION ACTIVITY AS A FUNCTION OF STELLAR MASS IN GALAXIES SINCE z similar to 3 査読有り

    M. Kajisawa, T. Ichikawa, T. Yamada, Y. K. Uchimoto, T. Yoshikawa, M. Akiyama, M. Onodera

    ASTROPHYSICAL JOURNAL 723 (1) 129-145 2010年11月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/723/1/129  

    ISSN:0004-637X

    eISSN:1538-4357

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    We study the evolution of star formation activity of galaxies at 0.5 &lt; z &lt; 3.5 as a function of stellar mass, using very deep NIR data taken with the Multi-Object Infrared Camera and Spectrograph on the Subaru telescope in the GOODS-North region. The NIR imaging data reach K similar to 23-24 Vega magnitude and they allow us to construct a nearly stellar-mass-limited sample down to similar to 10(9.5-10) M(circle dot) even at z similar to 3. We estimated star formation rates (SFRs) of the sample with two indicators, namely, the Spitzer/MIPS 24 mu m flux and the rest-frame 2800 angstrom luminosity. The SFR distribution at a fixed M(star) shifts to higher values with increasing redshift at 0.5 &lt; z &lt; 3.5. More massive galaxies show stronger evolution of SFR at z greater than or similar to 1. We found galaxies at 2.5 &lt; z &lt; 3.5 show a bimodality in their SSFR distribution, which can be divided into two populations by a constant SSFR of similar to 2 Gyr(-1). Galaxies in the low-SSFR group have SSFRs of similar to 0.5-1.0 Gyr(-1), while the high-SSFR population shows similar to 10 Gyr(-1). The cosmic SFR density (SFRD) is dominated by galaxies with M(star) = 10(10-11) M(circle dot) at 0.5 &lt; z &lt; 3.5, while the contribution of massive galaxies with M(star) = 10(11-11.5) M(circle dot) shows a strong evolution at z &gt; 1 and becomes significant at z similar to 3, especially in the case with the SFR based on MIPS 24 mu m. In galaxies with M(star) = 10(10-11.5) M(circle dot), those with a relatively narrow range of SSFR (less than or similar to 1 dex) dominates the cosmic SFRD at 0.5 &lt; z &lt; 3.5. The SSFR of galaxies that dominate the SFRD systematically increases with redshift. At 2.5 &lt; z &lt; 3.5, the high-SSFR population, which is relatively small in number, dominates the SFRD. Major star formation in the universe at higher redshift seems to be associated with a more rapid growth of stellar mass of galaxies.

  133. Fibre Multi-Object Spectrograph (FMOS) for the Subaru Telescope 査読有り

    Masahiko Kimura, Toshinori Maihara, Fumihide Iwamuro, Masayuki Akiyama, Naoyuki Tamura, Gavin B. Dalton, Naruhisa Takato, Philip Tait, Kouji Ohta, Shigeru Eto, Daisaku Mochida, Brian Elms, Kaori Kawate, Tomio Kurakami, Yuuki Moritani, Junichi Noumaru, Norio Ohshima, Masanao Sumiyoshi, Kiyoto Yabe, Jurek Brzeski, Tony Farrell, Gabriella Frost, Peter R. Gillingham, Roger Haynes, Anna M. Moore, Rolf Muller, Scott Smedley, Greg Smith, David G. Bonfield, Charles B. Brooks, Alan R. Holmes, Emma Curtis Lake, Hanshin Lee, Ian J. Lewis, Tim R. Froud, Ian A. Tosh, Guy F. Woodhouse, Colin Blackburn, Robert Content, Nigel Dipper, Graham Murray, Ray Sharples, David J. Robertson

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 62 (5) 1135-1147 2010年10月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/62.5.1135  

    ISSN:0004-6264

    eISSN:2053-051X

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    Fibre Multi-Object Spectrograph (FMOS) is the first near-infrared instrument with a wide field of view capable of acquiring spectra simultaneously from up to 400 objects. It has been developed as a common-use instrument for the F/2 prime-focus of the Subaru Telescope. The field coverage of 30' diameter is achieved using a new 3-element corrector optimized in the near-infrared (0.9-1.8 mu m) wavelength range. Due to limited space at the prime-focus, we have had to develop a novel fibre positioner, called "Echidna", together with two OH-airglow suppressed spectrographs. FMOS consists of three subsystems: the prime focus unit for IR, the fibre positioning system/connector units, and the two spectrographs. After full systems integration, FMOS was installed on the telescope in late 2007. Many aspects of the performance were checked through various test and engineering observations. In this paper, we present the optical and mechanical components of FMOS, and show the results of our on-sky engineering observations to date.

  134. MOIRCS DEEP SURVEY. VI. NEAR-INFRARED SPECTROSCOPY OF K-SELECTED STAR-FORMING GALAXIES AT z similar to 2 査読有り

    Tomohiro Yoshikawa, Masayuki Akiyama, Masaru Kajisawa, David M. Alexander, Kouji Ohta, Ryuji Suzuki, Chihiro Tokoku, Yuka K. Uchimoto, Masahiro Konishi, Toru Yamada, Ichi Tanaka, Koji Omata, Tetsuo Nishimura, Anton M. Koekemoer, Niel Brandt, Takashi Ichikawa

    ASTROPHYSICAL JOURNAL 718 (1) 112-132 2010年7月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/718/1/112  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present the results of near-infrared multi-object spectroscopic observations for 37 BzK-color-selected star-forming galaxies conducted with MOIRCS on the Subaru Telescope. The sample is drawn from the K-s-bandselected catalog of the MOIRCS Deep Survey in the GOODS-N region. About half of our samples are selected from the publicly available 24 mu m-source catalog of the Multiband Imaging Photometer for Spitzer on board the Spitzer Space Telescope. Ha emission lines are detected from 23 galaxies, of which the median redshift is 2.12. We derived the star formation rates (SFRs) from extinction-corrected Ha luminosities. The extinction correction is estimated from the spectral energy distribution (SED) fitting of multiband photometric data covering UV to near-infrared wavelengths. The Balmer decrement of the stacked emission lines shows that the amount of extinction for the ionized gas is larger than that for the stellar continuum. From a comparison of the extinction-corrected Ha luminosity and other SFR indicators, we found that the relation between the dust properties of stellar continuum and ionized gas is different depending on the intrinsic SFR (differential extinction). We compared SFRs estimated from extinction-corrected Ha luminosities with stellar masses estimated from SED fitting. The comparison shows no correlation between SFR and stellar mass. Some galaxies with stellar mass smaller than similar to 10(10) M-circle dot show SFRs higher than similar to 100 M-circle dot yr(-1). The specific SFRs (SSFRs) of these galaxies are remarkably high; galaxies which have SSFR higher than similar to 10(-8) yr(-1) are found in eight of the present sample. From the best-fit parameters of SED fitting for these high-SSFR galaxies, we find that the average age of the stellar population is younger than 100 Myr, which is consistent with the implied high SSFR. The large SFR implies the possibility that the high-SSFR galaxies significantly contribute to the cosmic SFR density of the universe at z similar to 2. When we apply the larger extinction correction for the ionized gas or the differential extinction correction, the total SFR density estimated from the H alpha-emission-line galaxies is 0.089-0.136 M-circle dot yr(-1) Mpc(-3), which is consistent with the total SFR densities in the literature. The metallicity of the high-SSFR galaxies, which is estimated from the N2 index, is larger than that expected from the mass-metallicity relation of UV-selected galaxies at z similar to 2 by Erb et al.

  135. X-ray groups and clusters of galaxies in the Subaru-XMM Deep Field 査読有り

    A. Finoguenov, M. G. Watson, M. Tanaka, C. Simpson, M. Cirasuolo, J. S. Dunlop, J. A. Peacock, D. Farrah, M. Akiyama, Y. Ueda, V. Smolcic, G. Stewart, S. Rawlings, C. van Breukelen, O. Almaini, L. Clewley, D. G. Bonfield, M. J. Jarvis, J. M. Barr, S. Foucaud, R. J. McLure, K. Sekiguchi, E. Egami

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 403 (4) 2063-2076 2010年4月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1111/j.1365-2966.2010.16256.x  

    ISSN:0035-8711

    eISSN:1365-2966

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    We present the results of a search for galaxy clusters in the Subaru-XMM Deep Field (SXDF). We reach a depth for a total cluster flux in the 0.5-2 keV band of 2 x 10(-15) erg cm(-2) s(-1) over one of the widest XMM-Newton contiguous raster surveys, covering an area of 1.3 deg(2). Cluster candidates are identified through a wavelet detection of extended X-ray emission. The red-sequence technique allows us to identify 57 cluster candidates. We report on the progress with the cluster spectroscopic follow-up and derive their properties based on the X-ray luminosity and cluster scaling relations. In addition, three sources are identified as X-ray counterparts of radio lobes, and in three further sources, an X-ray counterpart of the radio lobes provides a significant fraction of the total flux of the source. In the area covered by near-infrared data, our identification success rate achieves 86 per cent. We detect a number of radio galaxies within our groups, and for a luminosity-limited sample of radio galaxies we compute halo occupation statistics using a marked cluster mass function. We compare the cluster detection statistics in the SXDF with that in the literature and provide the modelling using the concordance cosmology combined with current knowledge of the X-ray cluster properties. The joint cluster log(N) - log(S) is overpredicted by the model, and an agreement can be achieved through a reduction of the concordance sigma(8) value by 5 per cent. Having considered the dn/dz and the X-ray luminosity function of clusters, we conclude that to pin down the origin of disagreement a much wider (50 deg(2)) survey is needed.

  136. Stellar populations of Ly alpha emitters at z=3-4 based on deep large area surveys in the Subaru-SXDS/UKIDSS-UDS Field 査読有り

    Yoshiaki Ono, Masami Ouchi, Kazuhiro Shimasaku, Masayuki Akiyama, James Dunlop, Duncan Farrah, Janice C. Lee, Ross McLure, Sadanori Okamura, Makiko Yoshida

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 402 (3) 1580-1598 2010年3月

    出版者・発行元:WILEY-BLACKWELL PUBLISHING, INC

    DOI: 10.1111/j.1365-2966.2009.16034.x  

    ISSN:0035-8711

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    We investigate the stellar populations of Ly alpha emitters (LAEs) at z = 3.1 and 3.7 in 0.65 deg2 of the Subaru/XMM-Newton Deep Field, based on rest-frame ultraviolet-to-optical photometry obtained from the Subaru/XMM-Newton Deep Survey, the UKIRT Infrared Deep Sky Survey/Ultra Deep Survey (UKIDSS/UDS), and the Spitzer legacy survey of the UKIDSS/UDS. Among a total of 302 LAEs (224 for z = 3.1 and 78 for z = 3.7), only 11 are detected in the K band, i.e. brighter than K(3 Sigma) = 24.1 mag. Eight of the 11 K-detected LAEs are spectroscopically confirmed. In our stellar population analysis, we treat K-detected objects individually, while K-undetected objects are stacked at each redshift. We find that the K-undetected objects, which should closely represent the LAE population as a whole, have low stellar masses of similar to 108-108.5 M(circle dot), modest star formation rates (SFRs) of 1-100 M(circle dot) yr-1, and modest dust extinction of E(B - V)(star) < 0.2. The K-detected objects are massive, M(star) similar to 109-1010.5 M(circle dot), and have significant dust extinction with a median of E(B - V)(star) similar or equal to 0.3. Four K-detected objects with the reddest spectral energy distributions, two of which are spectroscopically confirmed, are heavily obscured with E(B - V)(star) similar to 0.65, and their continua resemble those of some local ultraluminous infrared galaxies (ULIRGs). Interestingly, they have large Ly alpha equivalent widths similar or equal to 70-250 A. If these four are excluded, our sample has a weak anticorrelation between Ly alpha equivalent width and M(star). We compare the stellar masses and the specific SFRs (sSFRs) of LAEs with those of Lyman-break galaxies (LBGs), distant red galaxies, submillimetre galaxies, and I- or K-selected galaxies with photometric redshifts of z(phot) similar to 3. We find that the LAE population is the least massive among all the galaxy populations in question, but with relatively high sSFRs, while near-infrared (NIR)-detected LAEs have M(star) and sSFR similar to LBGs. Our reddest four LAEs have very high sSFRs in spite of large M(star), thus occupying a unique region in the M(star) versus sSFR space.

  137. MOIRCS DEEP SURVEY. V. A UNIVERSAL RELATION FOR STELLAR MASS AND SURFACE BRIGHTNESS OF GALAXIES

    Takashi Ichikawa, Masaru Kajisawa, Toru Yamada, Masayuki Akiyama, Tomohiro Yoshikawa, Masato Onodera, Masahiro Konishi

    ASTROPHYSICAL JOURNAL 709 (2) 741-748 2010年2月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/709/2/741  

    ISSN:0004-637X

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    We present a universal linear correlation between the stellar mass and surface brightness (SB) of galaxies at 0.3 < z < 3, using a deep K-band-selected catalog in the GOODS-North region. The correlation has a nearly constant slope, independent of redshift and color of galaxies in the rest-z frame. Considering unresolved compact galaxies, the tight correlation gives a lower boundary of SB for a given stellar mass; lower SB galaxies are prohibited over the boundary. The universal slope suggests that the stellar mass in galaxies was built up over their cosmic histories in a similar manner irrelevant to galaxy mass, as opposed to the scenario that massive galaxies mainly accumulated their stellar mass by major merging. In contrast, SB shows a strong dependence on redshift for a given stellar mass. It evolves as similar to(1+ z)(-2.0 similar to- 0.8), in addition to dimming as (1+z)(4) by the cosmological expansion effect. The brightening depends on galaxy color and stellar mass. The blue population (rest-frame U - V < 0), which is dominated by young and star-forming galaxies, evolves as similar to(1 + z)(-0.8 +/- 0.3) in the rest-V band. On the other hand, the red population (U - V > 0) and the massive galaxies (M(*) > 10(10) M(circle dot)) show stronger brightening, (1 + z)(-1.5 +/- 0.1). By comparison with galaxy evolution models, the phenomena are well understood by the pure luminosity evolution of galaxies out to z similar to 3.

  138. Raven, a harbinger of Multi-Object Adaptive Optics based instruments at the Subaru telescope

    Rodolphe Conan, Colin Bradley, Olivier Lardiere, Celia Blain, Kim Venn, David Andersen, Luc Simard, Jean-Pierre Veran, Glen Herriot, David Loop, Tomonori Usuda, Shin Oya, Yutaka Hayano, Hiroshi Terada, Masayuki Akiyama

    ADAPTIVE OPTICS SYSTEMS II 7736 2010年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.856567  

    ISSN:0277-786X

    eISSN:1996-756X

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    In the context of instrumentation for Extremely Large Telescopes (ELTs), an Integral Field Spectrographs (IFSs), fed with a Multi-Object Adaptive Optics (MOAO) system, has many scientific and technical advantages. Integrated with an ELT, a MOAO system will allow the simultaneous observation of up to 20 targets in a several arc-minute field-of-view, each target being viewed with unprecedented sensitivity and resolution. However, before building a MOAO instrument for an ELT, several critical issues, such as open-loop control and calibration, must be solved. The Adaptive Optics Laboratory of the University of Victoria, in collaboration with the Herzberg Institute of Astrophysics, the Subaru telescope and two industrial partners, is starting the construction of a MOAO pathfinder, called Raven. The goal of Raven is two-fold: first, Raven has to demonstrate that MOAO technical challenges can be solved and implemented reliably for routine on-sky observations. Secondly, Raven must demonstrate that reliable science can be delivered with multiplexed AO systems. In order to achieve these goals, the Raven science channels will be coupled to the Subaru's spectrograph (IRCS) on the infrared Nasmyth platform. This paper will present the status of the project, including the conceptual instrument design and a discussion of the science program.

  139. MOAO activities in Tohoku University

    Masayuki Akiyama, Shin Oya, Kazuhiro Hane, Tong Wu, Chihiro Tohoku

    ADAPTIVE OPTICS SYSTEMS II 7736 87 2010年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.857415  

    ISSN:0277-786X

    eISSN:1996-756X

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    We started adaptive optics (AO) development activities in Tohoku university targeting Multi-Object Adaptive Optics (MOAO) system for the next generation ground-based large telescopes. In order to realize an MOAO system, we are currently conducting two R&Ds. First one is a development of a large stroke (20 mu m) Micro Electro Mechanical Systems (MEMS) deformable mirror with large number of elements (>3000) which is necessary to achieve mild Strehl Ratio in an AO systems for 30m class telescopes. Based on our original design to achieve the requirements, prototyping of the device is currently underway using the MEMS development facility in our university. Second one is a consideration of tomographic algorithm for the wavefront estimation required for an MOAO system. The algorithm will be tested on a test bench simulating multiple guide stars and wavefront sensors. Concept design of the test bench is shown. MEMS-DM and MOAO testbed developments will be concluded by 2013.

  140. LYMAN BREAK GALAXIES AT z similar to 5: REST-FRAME UV SPECTRA. III. 査読有り

    Hiroki Kajino, Kouji Ohta, Ikuru Iwata, Kiyoto Yabe, Suraphong Yuma, Masayuki Akiyama, Naoyuki Tamura, Kentaro Aoki, Marcin Sawicki

    ASTROPHYSICAL JOURNAL 704 (1) 117-125 2009年10月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/704/1/117  

    ISSN:0004-637X

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    We present results of optical spectroscopic observations of candidates of Lyman break galaxies (LBGs) at z similar to 5 in the region, including the GOODS-N and the J0053+1234 regions by using Gemini Multi-Object Spectrograph North and South, respectively. Among 25 candidates, five objects are identified to be at z similar to 5 (two of them were already identified by an earlier study) and one object very close to the color-selection window turned out to be a foreground galaxy. With this spectroscopically identified sample and those from previous studies, we derived the lower limits on the number density of bright (M(UV) < -22.0 mag) LBGs at z similar to 5. These lower limits are comparable to or slightly smaller than the number densities of UV luminosity functions (UVLFs) that show the smaller number density among z similar to 5 UVLFs in literature. However, by considering that there remain many LBG candidates without spectroscopic observations, the number density of bright LBGs is expected to increase by a factor of two or more. The evidence for the deficiency of UV luminous LBGs with large Ly alpha equivalent widths was reinforced. We discuss possible causes for the deficiency and prefer the interpretation of dust absorption.

  141. MOIRCS DEEP SURVEY. IV. EVOLUTION OF GALAXY STELLAR MASS FUNCTION BACK TO z similar to 3

    M. Kajisawa, T. Ichikawa, I. Tanaka, M. Konishi, T. Yamada, M. Akiyama, R. Suzuki, C. Tokoku, Y. K. Uchimoto, T. Yoshikawa, M. Ouchi, I. Iwata, T. Hamana, M. Onodera

    ASTROPHYSICAL JOURNAL 702 (2) 1393-1412 2009年9月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/702/2/1393  

    ISSN:0004-637X

    eISSN:1538-4357

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    We use very deep near-infrared (NIR) imaging data obtained in MOIRCS Deep Survey (MODS) to investigate the evolution of the galaxy stellar mass function back to z similar to 3. The MODS data reach J = 24.2, H = 23.1, and K = 23.1 (5 sigma, Vega magnitude) over 10(3) arcmin(2) (wide) and J = 25.1, H = 23.7, and K = 24.1 over 28 arcmin(2) (deep) in the GOODS-North region. The wide and very deep NIR data allow us to measure the number density of galaxies down to low stellar mass (10(9)-10(10) M-circle dot) even at high redshift with high statistical accuracy. The normalization of the mass function decreases with redshift, and the integrated stellar mass density becomes similar to 8%-18% of the local value at z similar to 2 and similar to 4%-9% at z similar to 3, which are consistent with results of previous studies in general fields. Furthermore, we found that the low-mass slope becomes steeper with redshift from alpha similar to -1.3 at z similar to 1 to alpha similar to -1.6 at z similar to 3 and that the evolution of the number density of low-mass (10(9)-10(10) M-circle dot) galaxies is weaker than that of M* (similar to 10(11) M-circle dot) galaxies. This indicates that the contribution of low-mass galaxies to the total stellar mass density has been significant at high redshift. The steepening of the low-mass slope with redshift is an opposite trend expected from the stellar mass dependence of the specific star formation rate reported in previous studies. The present result suggests that the hierarchical merging process overwhelmed the effect of the stellar mass growth by star formation and was very important for the stellar mass assembly of these galaxies at 1 less than or similar to z less than or similar to 3.

  142. MOIRCS DEEP SURVEY. III. ACTIVE GALACTIC NUCLEI IN MASSIVE GALAXIES AT z=2-4 査読有り

    T. Yamada, M. Kajisawa, M. Akiyama, T. Ichikawa, M. Konishi, T. Nishimura, K. Omata, R. Suzuki, I. Tanaka, C. Tokoku, Y. K. Uchimoto, T. Yoshikawa

    ASTROPHYSICAL JOURNAL 699 (2) 1354-1364 2009年7月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/699/2/1354  

    ISSN:0004-637X

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    We investigate the X-ray properties of the K-band-selected galaxies at redshift 2 &lt; z &lt; 4 by using our deep near-infrared images obtained in the Multi-Object Infrared Camera and Spectrograph Deep Survey project and the published Chandra X-ray source catalog. Sixty-one X-ray sources with the 2-10 keV luminosity L(X) = 10(42)-10(44) erg s(-1) are identified with the K-selected galaxies and we found that they are exclusively (90%) associated with the massive objects with a stellar mass larger than 10(10.5) M(circle dot). Our results are consistent with the idea that the M(BH)/M(str) ratio of the galaxies at z = 2-4 is similar to the present-day value. On the other hand, the active galactic nucleus (AGN) detection rate among the very massive galaxies with a stellar mass larger than 10(11) M(circle dot) is high, 33% (26/78). They are active objects in the sense that the black hole mass accretion rate is approximate to 1%-50% of the Eddington limit if they indeed have similar M(BH)/M(str) ratio with those observed in the local universe. The active duration in the AGN duty cycle of the high-redshift massive galaxies seems large.

  143. Evidence of a link between the evolution of clusters and their AGN fraction

    Caroline van Breukelen, Chris Simpson, Steve Rawlings, Masayuki Akiyama, David Bonfield, Lee Clewley, Matt J. Jarvis, Tom Mauch, Tony Readhead, Ann-Marie Stobbart, Mark Swinbank, Mike Watson

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 395 (1) 11-27 2009年5月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1111/j.1365-2966.2009.14513.x  

    ISSN:0035-8711

    eISSN:1365-2966

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    We discuss the optical properties, X-ray detections and active galactic nucleus (AGN) populations of four clusters at z similar to 1 in the Subaru-XMM Deep Field (SXDF). The velocity distribution and plausible extended X-ray detections are examined, as well as the number of X-ray point sources and radio sources associated with the clusters. We find that the two clusters that appear virialized and have an extended X-ray detection contain few, if any, AGN, whereas the two pre-virialized clusters have a large AGN population. This constitutes evidence that the AGN fraction in clusters is linked to the clusters' evolutionary stage. The number of X-ray AGN in the pre-virialized clusters is consistent with an overdensity of a factor of similar to 200; the radio AGN appear to be clustered with a factor of 3 to 6 higher. The median K-band luminosities of L-K = 1.7 +/- 0.7 L* for the X-ray sources and L-K = 2.3 +/- 0.1 L* for the radio sources support the theory that these AGN are triggered by galaxy interaction and merging events in sub-groups with low internal velocity distributions, which make up the cluster environment in a pre-virialization evolutionary stage.

  144. DISCOVERY OF A GIANT Lyα EMITTER NEAR THE REIONIZATION EPOCH 査読有り

    Masami Ouchi, Yoshiaki Ono, Eiichi Egami, Tomoki Saito, Masamune Oguri, Patrick J. McCarthy, Duncan Farrah, Nobunari Kashikawa, Ivelina Momcheva, Kazuhiro Shimasaku, Kouichiro Nakanishi, Hisanori Furusawa, Masayuki Akiyama, James S. Dunlop, Angela M, J. Mortier, Sadanori Okamura, Masao Hayashi, Michele Cirasuolo, Alan Dressler, Masanori Iye, Matt J. Jarvis, Tadayuki Kodama, Crystal L. Martin, Ross J. McLure, Kouji Ohta, Toru Yamada, Michitoshi Yoshida

    The Astrophysical Journal 696 (2) 1164-1175 2009年5月

    出版者・発行元:{IOP} Publishing

    DOI: 10.1088/0004-637X/696/2/1164  

    ISSN:0004-637X

    eISSN:1538-4357

  145. CO-EVOLUTION OF SUPERMASSIVE BLACK HOLE AND HOST GALAXY FROM z similar to 1 TO z=0 査読有り

    Gaku Kiuchi, Kouji Ohta, Masayuki Akiyama

    ASTROPHYSICAL JOURNAL 696 (1) 1051-1062 2009年5月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/696/1/1051  

    ISSN:0004-637X

    eISSN:1538-4357

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    Stellar masses of bulges in hosts of active galactic nuclei (AGNs) and black hole masses in the AGNs are derived at z = 0.5-1.15 to study evolution of the black hole-to-bulge mass relation. In order to derive bulge stellar masses, we use a sample of type-2 AGNs to avoid the bright nuclear light. 34 type-2 AGNs are selected from the spectroscopically identified X-ray sources in the Chandra Deep Field South. We use optical images from the Hubble Space Telescope, and near-and mid-infrared photometry from the Very Large Telescope and the Spitzer Space Telescope. The bulge components are derived by fitting the two-dimensional surface brightness model consisting of a bulge and a disk component to the optical images. We derive stellar masses (M-bulge) and star formation rates (SFRs) of the bulge components by spectral energy distribution fitting. The derived M-bulge ranges over 10(9)-10(11) M-circle dot, and the estimated SFR is 0.01-100 M-circle dot yr(-1). Masses of supermassive black holes (SMBHs; M-lozenge) and black hole accretion rates (BHARs) are estimated with the absorption-corrected X-ray luminosities in the 2-10 keV band under an assumption of the constant Eddington ratio of 0.1 and the constant energy conversion factor of 0.1. Resulting black hole masses and BHARs range over 10(5.5)-10(8) M-circle dot and 0.001-1 M-circle dot yr(-1), respectively. For luminous AGNs, the estimated M-lozenge/M-bulge ratio is similar to 4 x 10(-4) in the median, which is lower than that for local galaxies and for type-2 AGNs at z similar to 0.2. However, these differences are within uncertainty and are not significant. This can imply that SMBHs and their host galaxies are evolving almost holding the constant M-lozenge/M-bulge ratio from z similar to 1.0 to 0 in a cosmological timescale. Meanwhile, the estimated BHAR/SFR ratio is about 60 times larger than the M-lozenge/M-bulge ratio in the median value. This indicates that growths of SMBHs and their host bulges do not proceed simultaneously in a shorter timescale such as an AGN phase.

  146. The stellar populations of lyman break galaxies at z ∼ 5 査読有り

    K. Yabe, K. Ohta, I. Iwata, M. Sawicki, N. Tamura, M. Akiyama, K. Aoki

    Astrophysical Journal 693 (1) 507-533 2009年3月

    出版者・発行元:None

    DOI: 10.1088/0004-637X/693/1/507  

    ISSN:0004-637X

    eISSN:1538-4357

  147. Detections of Lyman Continuum from Star-Forming Galaxies at z~3 through Subaru/Suprime-Cam Narrow-Band Imaging 査読有り

    岩田生, 国立天文台岡山, 井上昭雄, 松田有一, ダーラム大, 古澤久徳, 林野友紀, 香西克己, 秋山正幸, 山田亨, 東北大, Burgarella, D.(マルセイユ天体物理学研, Deharveng, J.-M, マルセイユ天体物理

    The Astrophysical Journal 692 (2) 1287-1293 2009年2月

    出版者・発行元:None

    DOI: 10.1088/0004-637X/692/2/1287  

    ISSN:0004-637X

    eISSN:1538-4357

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    宇宙史の一大イベントであった「宇宙再イオン化」を引き起こしたイオン化光源の正体を解明するため、遠方銀河からのイオン化光子フラックスをすばる望遠鏡で測定した。イオン化光子のこれまでの検出例は2例しかなかったが、今回観測した198個の銀河のうち、17個からイオン化光子を検出した。また、検出したイオン化光子フラックスはこれまでの予想を大きく上回る強度であった。このことから、イオン化光源としての遠方銀河の役割はこれまで考えられていた以上に重要であることが分かった。

  148. Photometric H alpha and [O II] Luminosity Function of SDF and SXDF Galaxies: Implications for Future Baryon Oscillation Surveys 査読有り

    Sumiyoshi} Masanao, Totani} Tomonori, Oshige} Shunsuke, Glazebrook} Karl, Akiyama} Masayuki, Morokuma} Tomoki, Motohara} Kentaro, Shimasaku} Kazuhiro, Hayashi} Masao, Yoshida} Makiko, Kashikawa} Nobunari, Kodama} Tadayuki

    arXiv e-prints arXiv:0902.2064 2009年

  149. VizieR Online Data Catalog: Subaru/XMM-Newton deep survey IV. (SXDS) (Ouchi+, 2008) 査読有り

    Ouchi} M, Shimasaku} K, Akiyama} M, Simpson} C, Saito} T, Ueda} Y, Furusawa} H, Sekiguchi} K, Yamada} T, Kodama} T, Kashikawa} N, Okamura} S, Iye} M, Takata} T, Yoshida} M, Yoshida} M

    VizieR Online Data Catalog J/ApJS/176/301 2009年

  150. An extreme EXO: a type 2 QSO at z=1.87 査読有り

    A. Del Moro, M. G. Watson, S. Mateos, M. Akiyama, Y. Hashimoto, N. Tamura, K. Ohta, F. J. Carrera, G. Stewart

    ASTRONOMY & ASTROPHYSICS 493 (2) 445-451 2009年1月

    出版者・発行元:EDP SCIENCES S A

    DOI: 10.1051/0004-6361:200809665  

    ISSN:1432-0746

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    Aims. We aim to understand the multi-wavelength properties of 2XMM J123204+215255, the source with the most extreme X-ray-to-optical flux ratio amongst a sample of bright X-ray selected EXOs drawn from a cross-correlation of the 2XMMp catalogue with the SDSS-DR5 catalogue. Methods. We use 2XMMp X-ray data, SDSS-DR5, NOT and UKIRT optical/NIR photometric data and Subaru MOIRCS IR spectroscopy to study the properties of 2XMM J123204+215255. We created a model SED including an obscured QSO and the host galaxy component to constrain the optical/IR extinction and the relative contribution of the AGN and the galaxy to the total emission. Results. 2XMM J123204+215255 is a bright X-ray source with f(X) approximate to 10(-12) erg cm(-2) s(-1) (2-10 keV energy band) which has no detection down to a magnitude i' &gt; 25.2. NIR imaging reveals a faint K-band counterpart and NIR spectroscopy shows a single broad (FWHM similar or equal to 5300 km s(-1)) emission line, which is almost certainly H alpha at z = 1.87. The X-ray spectrum shows evidence of significant absorption (N-H &gt; 10(23) cm(-2)), typical of type 2 AGN, but the broad H alpha emission suggests a type 1 AGN classification. The very red optical/NIR colours (i' - K &gt; 5.3) strongly suggest significant reddening however. We find that simple modelling can successfully reproduce the NIR continuum and strongly constrain the intrinsic nuclear optical/IR extinction to AV approximate to 4, which turns out to be much smaller than the expected from the X-ray absorption (assuming Galactic gas-to-dust ratio).

  151. THE SUBARU/XMM-NEWTON DEEP SURVEY (SXDS). III. X-RAY DATA

    Yoshihiro Ueda, Michael G. Watson, Ian M. Stewart, Masayuki Akiyama, Axel D. Schwope, Georg Lamer, Jacobo Ebrero, Francisco J. Carrera, Kazuhiro Sekiguchi, Tohru Yamada, Chris Simpson, Guenther Hasinger, Silvia Mateos

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 179 (1) 124-141 2008年11月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/591083  

    ISSN:0067-0049

    eISSN:1538-4365

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    We present the X-ray source catalog in the Subaru/XMM-Newton deep survey. A continuous area of 1.14 deg(2) centered at R:A:= 02(h)18(m) and decl. = -05 degrees is mapped by seven pointings with XMM-Newton covering the 0.2-10 keV band. From the combined images of the EPIC pn and MOS cameras, we detect 866, 1114, 645, and 136 sources with sensitivity limits of 6; 10 X 16, 8; 10 X 16, 3; 10 X 15, and 5; 10 x 15 ergs cm(-2) s(-1) in the 0.5-2, 0.5-4.5, 2-10, and 4.5-10 keV bands, respectively, with detection likelihood >= 7 (corresponding to a confidence level of 99.91%). The catalog consists of 1245 sources in total including 32 extended-source candidates. The averaged log N-log S relations are in good agreement with previous results, bridging the flux range between Chandra deep surveys and brighter surveys. The log N-log S relations show significant spatial variation among pointings on a scale of 0.2 deg(2). Analyzing the autocorrelation function, we detect significant clustering signals from the 0.5-2 keV band sample, which can be fit with a power-law form (theta/theta(c))(-0.8) with a correlation length of theta c = 5.9(-0.9)(+1.0) arcsec when the integral constraint terms included. In the 2-10 keV band, however, the clustering is not significant with a 90% upper limit of theta(c) < 1.5 ''.

  152. Subaru/MOIRCS Near-Infrared Imaging in the Proto-Cluster Region at z=3.1

    Yuka Katsuno Uchimoto, Ryuji Suzuki, Chihiro Tokoku, Takashi Ichikawa, Masahiro Konishi, Tomohiro Yoshikawa, Koji Omata, Tetsuo Nishimura, Toru Yamada, Ichi Tanaka, Masaru Kajisawa, Masayuki Akiyama, Yuichi Matsuda, Ryosuke Yamauchi, Tomoki Hayashino

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 60 (4) 683-693 2008年8月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/60.4.683  

    ISSN:0004-6264

    eISSN:2053-051X

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    We present the results of deep near-infrared imaging observations of the z = 3.1 proto-cluster region in the SSA 22a field taken by MOIRCS mounted on the Subaru Telescope. We observed a 21.7 arcmin(2) field to depths of J = 24.5, H = 24.3, and K = 23.9 (5 sigma). We examined the distribution of the K-selected galaxies at z similar to 3 by using a simple color cut for distant red galaxies (DRGs) as well as a photometric-redshift selection technique. The marginal density excess of DRGs and the photo-z selected objects were found around the two most luminous Ly alpha blobs (LABS). We investigated the correlation between the K-selected objects and the LABS, and found that several galaxies with stellar mass, M-* = 10(9)-10(11) M-circle dot, exist in the vicinity of LABS, especially around the two most luminous ones. We also found that 7 of the 8 LABS in the field have plausible K-s-band counterparts, and the sum of the stellar mass possibly associated with LABS correlates with their luminosity and surface brightness, which implies that the origin of Ly alpha emission may be closely correlated with their previous star-formation phenomena.

  153. Deep spectroscopy of systematically surveyed extended Ly alpha sources at z similar to 3-5

    Tomoki Saito, Kazuhiro Shimasaku, Sadanori Okamura, Masami Ouchi, Masayuki Akiyama, Michitoshi Yoshida, Yoshihiro Ueda

    ASTROPHYSICAL JOURNAL 675 (2) 1076-1094 2008年3月

    出版者・発行元:UNIV CHICAGO PRESS

    DOI: 10.1086/527282  

    ISSN:0004-637X

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    Spatially extended Ly alpha sources that are faint and/or compact in continuum are candidates for extremely young (less than or similar to 10(7) yr) galaxies at high redshifts. We present medium-resolution (R similar to 2000) VLT/VIMOS spectroscopy of 18 such extended Ly alpha sources found in our previous study at z similar to 3-5. The deep spectroscopy showed that all 18 objects have large equivalent widths (EWs), exceeding 100 angstrom in the rest frame. For about 30% of our sample (five objects), we identified conspicuous asymmetry in the profile of the Ly alpha line. They show broad wing emission components on the red side, and a sharp cutoff on the blue side of the Ly alpha line. Such asymmetry is often seen in superwind galaxies, and is also consistent with the theoretical prediction of superwinds. In fact, one of them shows systematic velocity structure in the two-dimensional spectrum, suggesting the existence of superwind activity. There are eight objects (8/18 similar to 40%) that have very large EWs, exceeding 200 angstrom (rest frame), and no clear signature of superwind activities. Such large EWs cannot be explained in terms of photoionization by a moderately old (> 10(7) yr) stellar population, even with a top-heavy IMF or an extremely low metallicity. These eight objects clearly show a positive correlation between the Ly alpha line luminosity and the velocity width. This suggests that these eight objects are good candidates for forming galaxies in a gas-cooling phase (cold accretion).

  154. The Subaru/XMM-Newton deep survey (SXDS). V. Optically faint variable object survey 査読有り

    Tomoki Morokuma, Mamoru Doi, Naoki Yasuda, Masayuki Akiyama, Kazuhiro Sekiguchi, Hisanori Furusawa, Yoshihiro Ueda, Tomonori Totani, Takeshi Oda, Tohru Nagao, Nobunari Kashikawa, Takashi Murayama, Masami Ouchi, Mike G. Watson, Michael W. Richmond, Christopher Lidman, Saul Perlmutter, Anthony L. Spadafora, Greg Aldering, Lifan Wang, Isobel M. Hook, Rob A. Knop

    ASTROPHYSICAL JOURNAL 676 (1) 163-183 2008年3月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/527467  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present our survey for optically faint variable objects using multiepoch ( 8-10 epochs over 2-4 years) i'- band imaging data obtained with Subaru Suprime-Cam over 0.918 deg(2) in the Subaru/XMM-Newton Deep Field (SXDF). We found 1040 optically variable objects by image subtraction for all the combinations of images at different epochs. This is the first statistical sample of variable objects at depths achieved with 8-10 m class telescopes or the Hubble Space Telescope. The detection limit for variable components is i'(vari) similar to 25.5 mag. These variable objects were classified into variable stars, supernovae ( SNe), and active galactic nuclei ( AGNs), based on the optical morphologies, magnitudes, colors, and optical-mid- infrared colors of the host objects, spatial offsets of variable components from the host objects, and light curves. Detection completeness was examined by simulating light curves for periodic and irregular variability. We detected optical variability for 36% +/- 2% ( 51% +/- 3% for a bright samplewith i' < 24.4mag) of X- ray sources in the field. Number densities of variable objects as functions of time intervals Delta t and variable component magnitudes i'vari are obtained. Number densities of variable stars, SNe, and AGNs are 120, 489, and 579 objects deg(-2), respectively. Bimodal distributions of variable stars in the color-magnitude diagrams indicate that the variable star sample consists of bright ( V similar to 22 mag) blue variable stars of the halo population and faint ( V similar to 23.5 mag) red variable stars of the disk population. There are a few candidates of RR Lyrae providing a possible number density of similar to 10(-2) kpc(-3) at a distance of > 150 kpc from the Galactic center.

  155. The Subaru/XMM-Newton deep survey (SXDS). VI. Properties of active galactic nuclei selected by optical variability 査読有り

    Tomoki Morokuma, Mamoru Doi, Naoki Yasuda, Masayuki Akiyama, Kazuhiro Sekiguchi, Hisanori Furusawa, Yoshihiro Ueda, Tomonori Totani, Takeshi Oda, Tohru Nagao, Nobunari Kashikawa, Takashi Murayama, Masami Ouchi, Mike G. Watson

    ASTROPHYSICAL JOURNAL 676 (1) 121-130 2008年3月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/528788  

    ISSN:0004-637X

    eISSN:1538-4357

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    We present the properties of active galactic nuclei (AGN) selected by optical variability in the Subaru/XMM-Newton Deep Field (SXDF). Based on the locations of variable components and light curves, 211 optically variable AGNs were reliably selected. We made three AGN samples; X-ray-detected optically nonvariable AGNs (XAs), X-ray-detected optically variable AGNs (XVAs), and X-ray-undetected optically variable AGNs (VAs). In the VA sample, we found a bimodal distribution of the ratio between the variable component flux and the host flux. One of these two components in the distribution, a class of AGNs with a faint variable component i'(vari) similar to 25 mag in bright host galaxies i' similar to 21 mag, is not seen in the XVA sample. These AGNs are expected to have low Eddington ratios if we naively consider a correlation between bulge luminosity and black hole mass. These galaxies have photometric redshifts z(photo) similar to 0.5 and we infer that they are low-luminosity AGNs with radiatively inefficient accretion flows (RIAFs). The properties of the XVA and VA objects and the differences from those of the XA objects can be explained within the unified scheme for AGNs. Optical variability selection for AGNs is an independent method and could provide a complementary AGN sample which even deep X-ray surveys have not found.

  156. Adaptive optics rest-frame V-band imaging of Lyman break galaxies at z similar to 3: High surface density disklike galaxies? 査読有り

    Masayuki Akiyama, Yosuke Minowa, Naoto Kobayashi, Kouji Ohta, Masataka Ando, Ikuru Iwata

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 175 (1) 1-28 2008年3月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/523670  

    ISSN:0067-0049

    eISSN:1538-4365

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    In order to reveal the rest-frame V-band morphology of galaxies at z similar to 3, we conducted AO-assisted K-band imaging observations of z similar to 3 LBGs whose absolute magnitudes range from M-V*-0.5 mag to M-V*+3.0 mag, with M-V*, the characteristic absolute magnitude of z similar to 3 LBGs, of -24.0 mag. The AO observations resolve most LBGs at a resolution of FWHM similar to 0.2 ''. The median apparent half-light radius, r(HL), is 0.23 '', i.e., 1.8 kpc at z = 3. LBGs brighter than M-V* have larger r(HL) (0.40 '') than the fainter LBGs (0.23 '') on average, and there are no bright LBGs with a small r(HL). LBGs brighter than M-V* have red rest-frame U-V colors (average of 0.2 mag), and most of the fainter LBGs show blue rest-frame U-V colors (average of -0.4 mag). The K-band peaks of some of the LBGs brighter than K 22: 0 mag show a significant shift from those in the optical images. We fit a Sersic profile to the images of the LBGs with K < 21: 5 mag, taking care of the uncertainty of the final PSFs at the position of the targets. The images of all but one LBG with K < 21: 5 mag are fitted well with Sersic profiles with n indexes less than 2, similar to disk galaxies in the local universe. For the fainter LBGs, we examine the concentration parameter instead of fitting a Sersic profile; the concentration parameters of the LBGs are consistent with those of disk galaxies. Assuming that the LBGs have a disk shape, we compared their size-luminosity and size-stellar mass relations with those of z 0 and z 1 disk galaxies. The LBGs are brighter than z = 0 and z = 1 disk galaxies at the same effective radius. The rest-frame V-band surface brightness of the LBGs are 2.2-2.9 mag and 1.2-1.9 mag brighter than the disk galaxies at z 0 and z 1, respectively. The size-stellar mass relation of the LBGs shows that the effective radii of the LBGs do not depend on their stellar mass. For LBGs brighter than M-V* , the average surface stellar mass density is 3-6 times larger than those of the z = 0 and z = 1 disk galaxies. On the contrary, the size-stellar mass relation of the less-luminous LBGs is similar to those of z = 0 and z = 1 disk galaxies. We also examine the profiles of the serendipitously observed DRGs. They are fitted with Sersic profiles with n < 2, and their scatter on the C versus rHL plane is similar to that of the z similar to 3 LBGs. The average surface stellar mass density of the DRGs is even larger than that of the z similar to 3 LBGs brighter than M-V*. The implications of the dominance of the n < 2 population among galaxies at z similar to 3 and the presence of the high surface stellar mass density disk systems are discussed.

  157. Integration, Commissioning and Performance of the UK FMOS Spectrograph

    Gavin B. Dalton, Ian J. Lewis, Ian A. J. Tosh, Colin Blackburn, David G. Bonfield, Charles B. Brooks, Alan R. Holmes, Hanshin Lee, Tim R. Froud, Masayuki Akiyama, Naoyukl Tamura, Naruhisa Takato

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY II, PTS 1-4 7014 2008年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.787619  

    ISSN:0277-786X

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    The UK FMOS spectrograph forms part of Subaru's FMOS multi-object infrared spectroscopy facility. The spectrograph was shipped to Hilo in component form in August of 2007. We describe the integration sequence for the spectrograph, the results of cooldown tests using a new chiller unit fitted to the spectrograph at the telescope, and alignment tests of the spectrograph, gratings and OH-suppression masks. We present the first-light observations for the spectrograph from May 2008.

  158. Differential Evolution of Lyman Break Galaxies from z=5 to 3

    Ikuru Iwata, Kouji Ohta, Marcin Sawicki, Naoyuki Tamura, Masayuki Akiyama, Kentaro Aoki

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 127-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We briefly summarize our findings front the unbiased surveys for z similar to 5 LBGs based on Subaru/Suprime-Cam and follow-up optical spectroscopy.

  159. Distant Red Galaxies in the MOIRCS Deep Survey

    Masaru Kajisawa, Masahiro Konishi, Takashi Ichikawa, Ryuji Suzuki, Chihiro Tokoku, Yuka Katsuno Uchimoto, Tomohiro Yoshikawa, Masayuki Akiyama, Masami Ouchi, Koji Omata, Ichi Tanaka, Tetsuo Nishimura, Toru Yamada

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 296-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We used very deep near-infrared imaging data taken with Subaru/MOIRCS in the MOIRCS Deep Survey (MODS) to investigate the number counts of distant red galaxies (DRCs) down to K-Vega = 23. We also performed the broad-band SED fitting analysis of galaxies at 2 < z < 4 with the combination. of MOIRCS and publicly available data from HST/ACS and Spitzer/IRAC to estimate the stellar mass, stellar age, and dust extinction of these galaxies.

  160. Near Infrared Photometry of Lyman-alpha Emitters at z=3.1 and 3.7 in the Subaru/XMM-Newton Deep Field

    Yoshiaki Ono, Kazuhiro Shimasaku, Masami Ouchi, Makiko Yoshida, Masayuki Akiyama, Sadanori Okamura

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 294-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We examine rest-frame far ultraviolet (FUV) (1500 angstrom) to optical (V) spectral energy distributions for Lyman-alpha emitters (LAEs) at z = 3.1 and 3.7 in a 1.22 deg(2) area of the Subaru/XMM-Newton Deep Field (SXDF), using multicolor data from the SXDS project (BV Riz) and the UKIDSS/UDS (JK). About 4% of our LAEs are detected in K, i.e., brighter than the 3 sigma magnitude (K = 24.0). W find that while the majority of the K-detected LAEs have a similar M-1500 - M-V vs M-1500 distribution to LBGs, a few have much redder M-1500 - M-V colors indicative of evolved and/or dusty stellar populations. In addition, a stacking analysis of K-undetected LAEs reveals that the vast majority of our LAEs are lower-mass counterparts to LBGs with similar colors.

  161. Search for Galaxies at the Cosmic Frontier

    Chihiro Tokoku, Masami Ouchi, Ryuji Suzuki, Toru Yamada, Masayuki Akiyama, Masaru Kajisawa, Ichi Tanaka, Masahiro Konishi, Tomohiro Yoshikawa, Yuka K. Uchimoto, Takashi Ichikawa

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 65-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We introduce our on-going search for Ly alpha emitters and z-dropouts at z = 7 - 9 in the GOODS-N field with Subaru/MOIRCS. In the course of MOIRCS Deep Survey started in 2006, we perform deep imaging with a set of broad- and narrow-band filters for z = 8.8 LAEs and z-dropouts. We plan to complete our observations by early 2009.

  162. Subaru/MOIRCS Near-Infrared Imaging in the Proto-Cluster Region at z=3.1

    Yuka Katsuno Uchimoto, Ryuji Suzuki, Chihiro Tokoku, Takashi Ichikawa, Masahiro Konishi, Tomohiro Yoshikawa, Koji Omata, Tetsuo Nishimura, Toru Yamada, Ichi Tanaka, Masaru Kajisawa, Masayuki Akiyama, Yuichi Matsuda, Ryosuke Yamauchi, Tomoki Hayashino

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 373-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    Using deep near-infrared imaging data taken by MOIRCS, we study K-selected objects in the z = 3.1 proto-cluster region in the SSA22a field. The distribution of galaxies at z similar to 3 is investigated by using the color cut for distant red galaxies (DRGs) and the photometric-redshift selection technique. The marginal density excess of DRGs and the photo-z selected objects is found around the two distinctive luminous Ly alpha blobs (LABs). We also find that the stellar mass derived for several galaxies in vicinity of each LAB is M* = 10(9) - 10(11)M(circle dot) and the sum of the stellar mass possibly associated with LABs increases with the. Lya luminosity and surface brightness. This result suggests that the origin of Lya emission appear to be correlated with the previous star formation.

  163. The Stellar Populations of Lyman-Break Galaxies at z similar to 5

    Kiyoto Yabe, Kouji Ohta, Ikuru Iwata, Marcin Sawicki, Naoyuki Tamura, Masayuki Akiyama, Kentaro Aoki

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 205-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We present the results of spectral energy distribution (SED) fitting analysis for Lyman-break galaxies (LBGs) at z similar to 5 in the. GOODS-N and its flanking fields. Row the SED fitting for similar to 100 objects, we found that the stellar masses range from 10(8) to 10(11) M-circle dot with a median value of 4 x 10(9) M-circle dot. By using the large sample of galaxies at z similar to 5, we construct the stellar mass function (SMF) with incompleteness corrections. By integrating down to 10(8) M-circle dot, the cosmic stellar mass density at z similar to 5 is calculated to be 7 x 10(6) M(circle dot)Mpc(-3).

  164. Subaru/XMM-Newton Deep Survey (SXDS) - Optical Imaging Survey and Photometric Catalogs 査読有り

    Hisanori Furusawa, George Kosugi, Masayuki Akiyama, Tadafumi Takata, Kazuhiro Sekiguchi, Junko Furusawa

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 131-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We present multi-waveband optical imaging data of the Subaru/XMM-Newton Deep Survey (SXDS). The SXDS has been the focus of wide range of multi-wavelength observing programs spanning the X-ray to the radio. The optical imaging observations are carried out with Suprime-Cam in the course of Subaru Telescope "Observatory Projects". A total area of 1.22 square degree is covered in five contiguous sub-fields, each of which corresponds to a single Suprime-Cam held of view (34' x 27'), in five broadband filters to the depths of B = 28.4, V = 27.8, R-0 = 27.7, i' = 27.7, and z' = 26.6 (AB, 3-sigma, phi-2arcsec). The data are reduced and compiled into five multi-waveband photometric catalogs, separately for each Suprime-Cam field. The i'-band catalogs contain about 900,000 objects in total, making the SXDS catalogs one of the largest multi-waveband object catalogs in corresponding depth and area coverage. The SXDS catalogs can be used for an extensive range of astronomical applications such as the number density study of the Galactic halo stars to the large scale structures it the distant universe. The number counts of galaxies are derived and compared with those of existing deep extragalactic surveys. Photometric redshifts of galaxies are estimated based on the optical data combined with near-infrared data derived front UKIDSS/UDS survey. The optical data, the source catalogs presented here are publicly available on the SXDS web page (http://www.naoj.org/Science/SubaruProject/SXDS/index.html).

  165. Wide-Field Optical Variability Survey for Low-Luminosity AGN with Suprime-Cam 査読有り

    Tomoki Morokuma, Mamoru Doi, Naoki Yasuda, Masayuki Akiyama, Kazuhiro Sekiguchi, Hisanori Furusawa, Nobunari Kashikawa, Tohru Nagao, Yoshihiro Ueda, Tomonori Totani, Takeshi Oda, Takashi Murayama, Masami Ouchi, Mike G. Watson

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 417-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We present our optical variability survey for low-luminosity active galactic nuclei (AGN) with Subaru Suprime Cam. We found that a significant fraction of variable AGN are not detected in deep x-ray data and about half of them can be low-luminosity AGN at z similar to 0.5. We also show a strong potential of optical variability as a tracer of high-z low-luminosity faint quasars.

  166. Testing the Target Selection for Future Spectroscopic BAO Surveys by SDF and SXDS Data

    Masanao Sumiyoshi, Shunsuke Oshige, Tomonori Totani, Karl Glazebrook, Masayuki Akiyama, Tomoki Morokuma, Kentaro Motohara, Kazuhiro Shimasaku, Makiko Yoshida, Masao Hayashi, Nobunari Kashikawa, Tadayuki Kodama

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 487-+ 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    Measuring the barionic acoustic oscillation (BAO) of large scale structure is a promising method to set strong constraints oil the nature of dark energy. In spectroscopic BAO surveys targeting emission line galaxies at high redshifts, it is required to select such emission line galaxies for spectroscopy efficiently from the imaging survey data. However, it is rather uncertain whether there are enough number of emission line galaxies for planned BAO surveys, and the requirements for imaging survey data for the pre-selection is not well known. Here, we estimate the surface number density of emission line galaxies by rising the wide and deep data of the Subaru Deep Field (SDF) and the Subaru XMM-Newton Deep Survey (SXDS). We estimate the star formation rate and line luminosities (11 alpha and 011) by SED fitting of the optical and NIR photometry data, and the method is calibrated by a test. applied to the SDSS galaxies. The derived It alpha and OII luminosity functions (LFs) are compared with those by other methods. We will report some implications for future BAO surveys based on these results.

  167. Performance of Echidna fiber positioner for FMOS on Subaru

    Masayuki Akiyama, Scott Smedley, Peter Gillingham, Jurek Brzeski, Tony Farrell, Masahiko Kimura, Rolf Muller, Naoyuki Tamura, Naruhisa Takato

    ADVANCED OPTICAL AND MECHANICAL TECHNOLOGIES IN TELESCOPES AND INSTRUMENTATION, PTS 1-3 7018 94 2008年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.788968  

    ISSN:0277-786X

    eISSN:1996-756X

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    Echidna is a fiber positioner designed and built by the Anglo-Australian Observatory using novel technology to position 400 fibers in the prime focus field of the Subaru telescope. The fibers feed two near infrared OH-suppression spectrographs, the whole project being known as Fiber Multi Object Spectrograph (FMOS). In order to accommodate the large number of the fibers in the physically limited area, a new fiber positioning method is developed. Stand-alone tests of the positioner at sea level confirm its performance is fully satisfactory. Initial results and propects of the on-sky commissioning tests of the positioner are also described.

  168. MOIRCS deep survey. II. Clustering properties of K-band selected galaxies in GOODS-North region

    Takashi Ichikawa, Ryuji Suzuki, Chihiro Tokoku, Yuka Katsuno Uchimoto, Masahiro Konishi, Tomohiro Yoshikawa, Masaru Kajisawa, Masami Ouchi, Takashi Hamana, Masayuki Akiyama, Tetsuo Nishimura, Koji Omata, Ichi Tanaka, Toru Yamada

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 59 (6) 1081-1094 2007年12月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/59.6.1081  

    ISSN:0004-6264

    eISSN:2053-051X

    詳細を見る 詳細を閉じる

    We present the first measurement of clustering properties of low-mass galaxies with a stellar mass down to M-* similar to 10(9)M(circle dot) at 1 < z < 4 in 24.4 arcmin(2) of the GOODS-North region with a depth of K-AB similar to 25. Luminous galaxies in the K-band have a larger correlation length than faint galaxies. For color-selected samples at 2 < z < 4, distant red galaxies with J-K > 1.3 show a large bias of b similar to 7.2 +/- 1.3 on scales of up to theta similar to 100 '' or 3.1 comoving Mpc, while blue galaxies with 0.5 < J-K < 1.3 have a weak clustering signal on large scales, but a possible strong small-scale excess at theta < 10 ''. For massive galaxies with M-* greater than or similar to 10(10)M(circle dot), we estimate the correlation length and bias to be r(0) similar to 4.5 h(-1) Mpc and b = 1.9-3.5, which are much larger than those of low-mass (M-* similar to 10(9)-10(10)M(circle dot)) galaxies. The comparison of our measurements with analytic CDM models constrains the properties of hosting dark halos, and indicates that the low-mass galaxies would be progenitors of galaxies with a typical luminosity of L less than or similar to L-* in the local Universe. The blue galaxies in low-mass samples are more strongly clustered in more massive halos with higher occupation numbers than low-mass red galaxies. This fact suggests an environment effect due to the halo mass on the star-formation activity at high-z.

  169. Lyman break galaxies at z similar to 5: Rest-frame UV spectra. II

    Masataka Ando, Kouji Ohta, Ikuru Iwata, Masayuki Akiyama, Kentaro Aoki, Naoyuki Tamura

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 59 (4) 717-726 2007年8月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/59.4.717  

    ISSN:0004-6264

    eISSN:2053-051X

    詳細を見る 詳細を閉じる

    We present spectroscopy results of Lyman break galaxies (LBGs) at z similar to 5 in the J0053+1234 field. Among five bright candidates with z' < 25.0 mag, two objects are confirmed to be at z similar to 5. The equivalent widths (EWs) of Ly alpha emission of the 2 LBGs are not so strong as to be detected as Lya emitters, and one of them shows strong low-ionization interstellar (LIS) metal absorption lines. Two faint objects with z' >= 25.0 mag are also confirmed to be at z similar to 5, and their spectra show strong Lya emission in contrast to bright ones. These results suggest a deficiency of strong Lya emission in bright LBGs at z similar to 5, as discussed in our previous paper. Combined with our previous spectra of LBGs at z similar to 5, obtained around the Hubble Deep Field-North (HDF-N), we made a composite spectrum of luminous M-1400 <= -21.5 mag) LBGs at z similar to 5. The resultant spectrum shows weak Lya emission and strong LIS absorptions, which suggest that the bright LBGs at z similar to 5 have chemically evolved at least to -0.1 solar metallicity. For a part of our sample in the HDF-N region, we obtained near-to-mid infrared data, which constrain the stellar masses of these objects. With the stellar mass and the metallicity estimated from the LIS absorptions, the metallicities of the LBGs at z similar to 5 tend to be lower than those of galaxies with the same stellar mass at z less than or similar to 2, although the uncertainty is very large.

  170. CO observations of a FeLoBAL quasar with an H alpha absorption line at z=2.3 査読有り

    Kouji Ohta, Gaku Kiuchi, Kouichiro Nakanishi, Kentaro Aoki, Ikuru Iwata, Masayuki Akiyama, Naoyuki Tamura, Masataka Ando

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 59 (3) 527-530 2007年6月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/59.3.527  

    ISSN:0004-6264

    eISSN:2053-051X

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    SDSS J083942.11 + 380526.3 is an Iron Low-ionization Broad Absorption Line (FeLoBAL) quasar at z = 2.3, and Aoki et al. (2006) recently found the presence of an H alpha absorption line in the broad H alpha emission line. Motivated by an idea that this quasar may be a huge molecular gas reservoir in the early phase of quasar evolution, we made CO(J = 3-2) observations of it using the Nobeyama Millimeter Array. No significant CO emission was detected; although an emission-like feature (2.5 sigma) was seen close (similar to 2 '') to the quasar, we regard it as noise. The obtained 3 sigma upper limit on the CO luminosity is L'(CO(J=3-2)) = 4.5 x 10(10) K km s(-1) pc(2), which corresponds to M(H-2) = 3.6 x 10(10)M(circle dot) if we adopt CO-to-H-2 conversion factor of 0.8 M-circle dot (K km s(-1) pc(2))(-1). This upper limit is comparable to L'(CO(J=3-2)) (and thus the molecular gas mass) detected in quasars and BAL quasars at z = 1-3, and no sign of the presence of the huge amount of molecular gas in this FeLoBAL quasar was obtained.

  171. The number density of old passively-evolving galaxies at z = 1 in the Subaru/XMM-Newton deep survey field (vol 634, pg 861, 2005) 査読有り

    Toru Yamada, Tadayuki Kodama, Masayuki Akiyama, Hisanori Furusawa, Ikuru Iwata, Masaru Kajisawa, Masanori Iye, Masami Ouchi, Kazuhiro Sekiguchi, Kazuhiro Shimasaku, Chris Simpson, Ichi Tanaka, Michitoshi Yoshida

    ASTROPHYSICAL JOURNAL 659 (1) 862-862 2007年4月

    出版者・発行元:UNIV CHICAGO PRESS

    DOI: 10.1086/510327  

    ISSN:0004-637X

  172. Errata : The SUBARU Deep Field Project: Lyman-alpha Emitters at a Redshift of 6.6 査読有り

    Taniguchi, Y, Ajiki, M, Nagao, T, Shioya, Y, Murayama, T, Kashikawa, N, Kodaira, K, Kaifu, N, Ando, H, Karoji, H, Akiyama, M, Aoki, K, Doi, M, Fujita, S. S, Furusawa, H, Hayashino, T, Iwamuro, F, Iye, M, Kobayashi, N, Kodama, T, Komiyama, Y, Matsuda, Y, Miyazaki, S, Mizumoto, Y, Morokuma, T, Motohara, K, Nariai, K, Ohta, K, Ohyama, Y, Okamura, S, Ouchi, M, Sasaki, T, Sato, Y, Sekiguchi, K, Shimasaku, K, Tamura, H, Umemura, M, Yamada, T, Yasuda, N, Yoshida, M

    Publications of the Astronomical Society of Japan 59 (1) 277-277 2007年2月25日

    DOI: 10.1093/pasj/59.1.277  

    ISSN:2053-051X

  173. The SUBARU deep field project: Lyman alpha emitters at a redshift of 6.6 (vol 57, pg 165, 2005) 査読有り

    Yoshiaki Taniguchi, Msaru Ajiki, Tohru Nagao, Yasuhiro Shioya, Takashi Murayama, Nobunari Kashikawa, Keiichi Kodaira, Norio Kaifu, Hiroyasu Ando, Hiroshi Karoji, Masayuki Akiyama, Kentaro Aoki, Mamoru Doi, Shinobu S. Fujita, Hisanori Furusawa, Tomoki Hayashino, Furnihide Iwamuro, Masanori Iye, Naoto Kobayashi, Tadayuki Kodama, Yutaka Komiyama, Yuichi Matsuda, Satoshi Miyazaki, Yoshihiko Mizumoto, Tomoki Morokuma, Kentaro Motohara, Kyoji Nariai, Koji Ohta, Youichi Ohyama, Sadanori Okamura, Masami Ouchi, Toshiyuki Sasaki, Yasunori Sato, Kazuhiro Sekiguchi, Kazuhiro Shimasaku, Hajime Tamura, Masayuki Umemura, Toru Yamada, Naoki Yasuda, Michitoshi Yoshida

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 59 (1) 277-277 2007年2月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/59.1.277  

    ISSN:0004-6264

    eISSN:2053-051X

  174. Host galaxies of hard X-ray selected type 2 active galactic nuclei at intermediate redshifts

    Gaku Kiuchi, Kouji Ohta, Masayuki Akiyama, Kentaro Aoki, Yoshihiro Ueda

    CENTRAL ENGINE OF ACTIVE GALACTIC NUCLEI 373 679-681 2007年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We studied host galaxies of 15 hard X-ray selected type 2 AGNs (median redshift is 0.22). Thanks to the intrinsic obscuration of a bright nucleus, we can decompose galaxies and derive spheroid luminosities. We can also derive a black hole masses in the sample AGNs from the absorption corrected X-ray luminosity assuming an Eddington ratio. The resultant black hole mass to spheroid luminosity relation at the redshifts does not show a significant evolution from z similar to 0.

  175. Differential evolution of the UV luminosity function of Lyman break galaxies from z ∼ 5 to 3 査読有り

    I. Iwata, K. Ohta, N. Tamura, M. Akiyama, K. Aoki, M. Ando, G. Kiuchi, M. Sawicki

    Monthly Notices of the Royal Astronomical Society 376 (4) 1557-1576 2007年

    DOI: 10.1111/j.1365-2966.2007.11557.x  

  176. Host galaxies of hard X-ray-selected type 2 active Galactic nuclei at intermediate redshifts (vol 647, pg 892, 2006) 査読有り

    Gaku Kiuchi, Kouji Ohta, Masayuki Akiyama, Kentaro Aoki, Yoshihiro Ueda

    ASTROPHYSICAL JOURNAL 653 (2) 1583-1583 2006年12月

    出版者・発行元:UNIV CHICAGO PRESS

    DOI: 10.1086/509803  

    ISSN:0004-637X

  177. Luminosity functions of lyman break galaxies at z similar to 4 and z similar to 5 in the Subaru Deep Field 査読有り

    Makiko Yoshida, Kazuhiro Shimasaku, Nobunari Kashikawa, Masami Ouchi, Sadanori Okamura, Masaru Ajiki, Masayuki Akiyama, Hiroyasu Ando, Kentaro Aoki, Mamoru Doi, Hisanori Furusawa, Tomoki Hayashino, Fumihide Iwamuro, Masanori Iye, Hiroshi Karoji, Naoto Kobayashi, Keiichi Kodaira, Tadayuki Kodama, Yutaka Komiyama, Matthew A. Malkan, Yuichi Matsuda, Satoshi Miyazaki, Yoshihiko Mizumoto, Tomoki Morokuma, Kentaro Motohara, Takashi Murayama, Tohru Nagao, Kyoji Nariai, Kouji Ohta, Toshiyuki Sasaki, Yasunori Sato, Kazuhiro Sekiguchi, Yasuhiro Shioya, Hajime Tamura, Yoshiaki Taniguchi, Masayuki Umemura, Toru Yamada, Naoki Yasuda

    ASTROPHYSICAL JOURNAL 653 (2) 988-1003 2006年12月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/508621  

    ISSN:0004-637X

    eISSN:1538-4357

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    We investigate the luminosity functions of Lyman break galaxies (LBGs) at z similar to 4 and z similar to 5 based on optical imaging data obtained in the Subaru Deep Field project. Three samples of LBGs in a contiguous area of 875 arcmin(2) are constructed. One consists of 3808 LBGs at z similar to 4 down to i' = 26.85 selected with the B-R versus R-i' diagram. The other two consist of 539 and 240 LBGs at z similar to 5 down to z' = 26.05 selected with two kinds of two-color diagram: V-i' versus i'-z' and R-i' versus i'-z'. The adopted selection criteria are proved to be fairly reliable by spectroscopic observations. We derive the luminosity functions of the LBGs at rest- frame ultraviolet wavelengths down to M-UV = -19.2 at z similar to 4 and M-UV = -20.3 at z similar to 5. We find clear evolution of the luminosity function over the redshift range 0 <= z <= 6, which is accounted for solely by a change in the characteristic magnitude M*. We examine the evolution of the cosmic star formation rate (SFR) density and its luminosity dependence over 0 <= z less than or similar to 6. The SFR density contributed from brighter galaxies is found to change more drastically with cosmic time. The contribution from brighter galaxies has a sharp peak around z = 3-4, while that from fainter galaxies evolves relatively mildly with a broad peak at earlier epochs. Combining the observed SFR density with the standard cold dark matter model, we compute the cosmic SFR per unit baryon mass in dark halos, that is, the specific SFR. The specific SFR is found to scale with redshift as (1 + z)(3) up to z similar to 4, implying that the efficiency of star formation is on average higher at higher redshift in proportion to the cooling rate within dark halos, while this is not simply the case at z greater than or similar to 4.

  178. Discovery of Hα absorption in the unusual broad absorption line quasar SDSS J083942.11+380526.3 査読有り

    K. Aoki, I. Iwata, K. Ohta, M. Ando, M. Akiyama, N. Tamura

    Astrophysical Journal Letters 651 (1) 84-92 2006年11月

    出版者・発行元:None

    DOI: 10.1086/507438  

    ISSN:0004-637X

    eISSN:1538-4357

  179. Systematic survey of extended Ly alpha sources over z 3-5

    Tomoki Saito, Kazuhiro Shimasaku, Sadanori Okamura, Masami Ouchi, Masayuki Akiyama, Michitoshi Yoshida

    ASTROPHYSICAL JOURNAL 648 (1) 54-66 2006年9月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/505678  

    ISSN:0004-637X

    eISSN:1538-4357

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    Spatially extended Ly alpha sources that are faint and compact in continuum are candidates for extremely young (less than or similar to 10(7) yr) galaxies at high redshifts. We carried out a systematic survey for extended Ly alpha sources, using deep intermediate-band imaging data taken with the Suprime-Cam on the Subaru Telescope. Our survey covers a field of view of 33' x 25' and a redshift range of 3.24 <= z <= 4.95, down to a Ly alpha flux of similar to 1 x 10(-17) ergs cm(-2) s(-1). We identified 41 extended Ly alpha sources. The redshift distribution of these sources shows that this kind of object is common in the early universe over the surveyed redshift range. The identified objects have typical sizes of similar to 10-15 kpc and luminosities of similar to 10(42) ergs s(-1). Follow-up spectroscopy made for 7 of the 41 objects showed that our sample suffers from little contamination. All 7 objects have large equivalent widths of Ly alpha emission line, all but one exceeding 240 8 in the rest frame. The large equivalent widths suggest that their extended Ly alpha emissions are unlikely to be due to normal starbursts, but possibly originate from very young galaxies. All 41 objects in our sample have much smaller Ly alpha luminosities than the two Ly alpha blobs (LABs) found at a z similar or equal to 3.1 protocluster, in spite of our much larger survey volume. This suggests that large and luminous extended Ly alpha objects like the two LABs are very rare and are clustered in over-dense regions.

  180. Host galaxies of hard X-ray-selected type 2 active galactic nuclei at intermediate redshifts 査読有り

    Gaku Kiuchi, Kouji Ohta, Masayuki Akiyama, Kentaro Aoki, Yoshihiro Ueda

    ASTROPHYSICAL JOURNAL 647 (2) 892-900 2006年8月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/505108  

    ISSN:0004-637X

    eISSN:1538-4357

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    We study properties of the host galaxies of 15 hard X-ray-selected type 2 active galactic nuclei (AGNs) at intermediate redshifts (0.05 < z < 0.6) detected in ASCA surveys. The absorption-corrected hard X-ray luminosities L2-10 keV range from 10(42) to 10(45) ergs s(-1). We took the R-band image of these AGNs with the University of Hawaii 2.2 m telescope. Thanks to the intrinsic obscuration of nuclear light, we can decompose the galaxies with a spheroid component and a disk component. The resulting spheroid luminosities correlate with L2-10 keV; higher ( lower) X-ray luminosity AGNs tend to reside in more luminous ( less luminous) spheroids. It is also found that the hosts of luminous AGNs show a large spheroid-to-disk luminosity ratio (similar to 1), while those of less luminous AGNs spread between 0 and 1. The correlation between L2-10 keV and spheroid luminosity indicates a relation between the mass of a supermassive black hole (SMBH) and the spheroid luminosity (BS relation) at intermediate redshifts. The BS relation agrees with that in the local universe if an Eddington ratio of 0.24 is adopted, which is a mean value determined from our ASCA type 1 AGN sample at similar redshifts through the broad line width and continuum luminosity. The present study demonstrates the effectiveness of using type 2 AGNs at high redshifts to study their host properties.

  181. Deficiency of large equivalent width Lyα emission in luminous lyman break galaxies at z ∼ 5-6?′ 査読有り

    M. Ando, K. Ohta, I. Iwata, M. Akiyama, K. Aoki, N. Tamura

    Astrophysical Journal Letters 645 (1) L9-L12 2006年7月

    出版者・発行元:None

    DOI: 10.1086/505652  

    ISSN:0004-637X

    eISSN:1538-4357

  182. FMOS: the fiber multiple-object spectrograph IV: current status of OHS-based spectrograph

    Fumihide Iwamuro, Toshinori Maihara, Kouji Ohta, Shigeru Eto, Michinari Sakai, Masayuki Akiyama, Masahiko Kimura, Naoyuki Tamura, Junichi Noumaru, Hiroshi Karoji, Gavin B. Dolton, Ian J. Lewis, Ian A. J. Tosh, Graham J. Murray, Nigel A. Dipper, David J. Robertoson, Peter R. Gillingham, Scott Smedley, Greg A. Smith, Gabriella. Frost

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY, PTS 1- 3 6269 2006年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.671006  

    ISSN:0277-786X

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    The Fiber Multiple-Object Spectrograph for Subaru Telescope (FMOS) is quite large instrument composed of the prime focus unit, the fiber bundle unit, and the two infrared spectrographs. Among these units, a part of the prime focus unit and one of the spectrograph were transported from Kyoto University to the Subaru observatory in the middle of 2005. We present the optical and the mechanical components of the spectrograph, which was reassembled on the new floor of the Subaru dome. We also show the preliminary results of the optical alignment and the cooling test of the instrument at the summit of Mauna Kea.

  183. FMOS: The Fibre Multi-Object Spectrograph V Results of early PIR engineering run - art. no. 626944

    Masahiko Kimura, Toshinori Maihara, Fumihide Iwamuro, Shigeru Eto, Masayuki Akiyama, Kouji Ohta, Michinari Sakai, Naoyuki Tamura, Daisaku Mochida

    Ground-based and Airborne Instrumentation for Astronomy, Pts 1- 3 6269 26944-26944 2006年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.670705  

    ISSN:0277-786X

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    Fibre Multi-Object Spectrograph (FMOS) is one of the second-generation instruments of Subaru Telescope. FMOS is consisted of a number of subsystems; the Prime focus unit for IR (called PIR), the fibre positioning system/connector units, and the two spectrographs. The PIR and one spectrograph were made in Kyoto University, and were brought to the Subaru telescope last spring. The PIR attached to the telescope and stellar images were obtained for optical alignment in July and October last year. We report on these engineering run in this proceeding.

  184. Infrared multi-object spectrograph of MOIRCS

    Chihiro Tokoku, Ryuji Suzuki, Koji Omata, Masahiro Konishi, Tomohiro Yoshikawa, Masayuki Akiyama, Ichi Tanaka, Takashi Ichikawa, Tetsuo Nishimura

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY, PTS 1- 3 6269 2006年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.672418  

    ISSN:0277-786X

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    The design, development, operation and current performance of MOS (multi-object spectroscopy) mode of MOIRCS is described. MOIRCS (Multi-Object Infrared Camera and Spectrograph) is one of the second-generation instruments for the Subaru Telescope and provides imaging and MOS modes with a 4' x 7' field of view for a wavelength range from 0.85 to 2.5 mu m. To achieve near-infrared(NIR) MOS up to K-band, MOS mode uses multi-slit masks and a mask exchange system in a cryogenic environment. The masks are housed in a vacuum dewar attached to the MOIRCS main dewar and separated by a large gate valve. The mask dewar is equipped with its own cryogenic cooler and a vacuum pump and is capable of storing eighteen masks. The masks are made of thin aluminum foil. Slits are cut with a laser, with software that corrects for the effects of thermal contraction. The masks are cooled to below 130 K in the mask dewar and transported to the focal plane in the main dewar through the gate valve with a linear motion manipulator. An interlock is equipped on the mask exchange system to secure the cryogenic instrument from accident. Replacing masks can be done in the daytime without breaking the vacuum of the main dewar by isolating the mask dewar with the gate valve. Acquisition occurs by iteratively taking on-sky images through alignment holes on the mask until the rotation and offset between alignment stars and alignment holes become small enough. MOIRCS/MOS mode will be open to the public in late 2006.

  185. Clustering of Lyman Break Galaxies at z = 4 and 5 in the Subaru Deep Field: Luminosity Dependence of the Correlation Function Slope 査読有り

    Kashikawa, N, Yoshida, M, Shimasaku, K, Nagashima, M, Yahagi, H, Ouchi, M, Matsuda, Y, Malkan, M. A, Doi, M, Iye, M, Ajiki, M, Akiyama, M, Ando, H, Aoki, K, Furusawa, H, Hayashino, T, Iwamuro, F, Karoji, H, Kobayashi, N, Kodaira, K, Kodama, T, Komiyama, Y, Miyazaki, S, Mizumoto, Y, Morokuma, T, Motohara, K, Murayama, T, Nagao, T, Nariai, K, Ohta, K, Okamura, S, Sasaki, T, Sato, Y, Sekiguchi, K, Shioya, Y, Tamura, H, Taniguchi, Y, Umemura, M, Yamada, T, Yasuda, N

    The Astrophysical Journal 637 (2) 631-647 2006年

    DOI: 10.1086/498403  

  186. The SUBARU Deep Field Project: Lyman-alpha Emitters at a Redshift of 6.6 査読有り

    Taniguchi, Y, Ajiki, M, Nagao, T, Shioya, Y, Murayama, T, Kashikawa, N, Kodaira, K, Kaifu, N, Ando, H, Karoji, H, Akiyama, M, Aoki, K, Doi, M, Fujita, S. S, Furusawa, H, Hayashino, T, Iwamuro, F, Iye, M, Kobayashi, N, Kodama, T, Komiyama, Y, Matsuda, Y, Miyazaki, S, Mizumoto, Y, Morokuma, T, Motohara, K, Nariai, K, Ohta, K, Ohyama, Y, Okamura, S, Ouchi, M, Sasaki, T, Sato, Y, Sekiguchi, K, Shimasaku, K, Tamura, H, Umemura, M, Yamada, T, Yasuda, N, Yoshida, M

    Publications of the Astronomical Society of Japan 57 165-182 2005年2月25日

    DOI: 10.1093/pasj/57.1.165  

    ISSN:2053-051X

  187. The Subaru Deep Field project: Lyman α emitters at a redshift of 6.6 査読有り

    Y. Taniguchi, M. Ajiki, T. Nagao, Y. Shioya, T. Murayama, N. Kashikawa, K. Kodaira, N. Kaifu, H. Ando, H. Karoji, M. Akiyama, K. Aoki, M. Doi, S.S. Fujita, H. Furusawa, T. Hayashino, F. Iwamuro, M. Iye, N. Kobayashi, T. Kodama, Y. Komiyama, Y. Matsuda, S. Miyazaki, Y. Mizumoto, T. Morokuma, K. Motohara, K. Nariai, K. Ohta, Y. Ohyama, S. Okamura, M. Ouchi, T. Sasaki, Y. Sato, K. Sekiguchi, K. Shimasaku, H. Tamura, M. Umemura, T. Yamada, N. Yasuda, M. Yoshida

    Publications of the Astronomical Society of Japan 57 (1) 165-182 2005年2月

    出版者・発行元:None

    DOI: 10.1093/pasj/57.1.165  

    ISSN:0004-6264

    eISSN:2053-051X

  188. The Number Density of Old Passively Evolving Galaxies atz = 1 in the Subaru/XMM‐NewtonDeep Survey Field 査読有り

    Toru Yamada, Tadayuki Kodama, Masayuki Akiyama, Hisanori Furusawa, Ikuru Iwata, Masaru Kajisawa, Masanori Iye, Masami Ouchi, Kazuhiro Sekiguchi, Kazuhiro Shimasaku, Chris Simpson, Ichi Tanaka, Michitoshi Yoshida

    The Astrophysical Journal 634 (2) 861-878 2005年

    出版者・発行元:{IOP} Publishing

    DOI: 10.1086/496954  

    ISSN:0004-637X

    eISSN:1538-4357

  189. The Discovery of Primeval Large-Scale Structures with Forming Clusters at Redshift 6 査読有り

    Ouchi} Masami, Shimasaku} Kazuhiro, Akiyama} Masayuki, Sekiguchi} Kazuhiro, Furusawa} Hisanori, Okamura} Sadanori, Kashikawa} Nobunari, Iye} Masanori, Kodama} Tadayuki, Saito} Tomoki, Sasaki} Toshiyuki, Simpson} Chris, Takata} Tadafumi, Yamada} Toru, Yamanoi} Hitomi, Yoshida} Makiko, Yoshida} Michitoshi

    \apjl 620 (1) L1-L4 2005年

    出版者・発行元:None

    DOI: 10.1086/428499  

    ISSN:0004-637X

  190. Definitive Identification of the Transition between Small- and Large-Scale Clustering for Lyman Break Galaxies 査読有り

    Ouchi} Masami, Hamana} Takashi, Shimasaku} Kazuhiro, Yamada} Toru, Akiyama} Masayuki, Kashikawa} Nobunari, Yoshida} Makiko, Aoki} Kentaro, Iye} Masanori, Saito} Tomoki, Sasaki} Toshiyuki, Simpson} Chris, Yoshida} Michitoshi

    \apjl 635 (2) L117-L120 2005年

    出版者・発行元:None

    DOI: 10.1086/499519  

    ISSN:0004-637X

  191. The Subaru Deep Field: The Optical Imaging Data 査読有り

    Kashikawa, N, Shimasaku, K, Yasuda, N, Ajiki, M, Akiyama, M, Ando, H, Aoki, K, Doi, M, Fujita, S. S, Furusawa, H, Hayashino, T, Iwamuro, F, Iye, M, Karoji, H, Kobayashi, N, Kodaira, K, Kodama, T, Komiyama, Y, Matsuda, Y, Miyazaki, S, Mizumoto, Y, Morokuma, T, Motohara, K, Murayama, T, Nagao, T, Nariai, K, Ohta, K, Okamura, S, Ouchi, M, Sasaki, T, Sato, Y, Sekiguchi, K, Shioya, Y, Tamura, H, Taniguchi, Y, Umemura, M, Yamada, T, Yoshida, M

    Publications of the Astronomical Society of Japan 56 1011-1023 2004年12月25日

    DOI: 10.1093/pasj/56.6.1011  

    ISSN:2053-051X

  192. The Subaru Deep Field: The optical imaging data 査読有り

    N Kashikawa, K Shimasaku, N Yasuda, M Ajiki, M Akiyama, H Ando, K Aoki, M Doi, SS Fujita, H Furusawa, T Hayashino, F Iwamuro, M Iye, H Karoji, N Kobayashi, K Kodaira, T Kodama, Y Komiyama, Y Matsuda, S Miyazaki, Y Mizumoto, T Morokuma, K Motohara, T Murayama, T Nagao, K Nariai, K Ohta, S Okamura, M Ouchi, T Sasaki, Y Sato, K Sekiguchi, Y Shioya, H Tamura, Y Taniguchi, M Umemura, T Yamada, M Yoshida

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 56 (6) 1011-1023 2004年12月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/56.6.1011  

    ISSN:0004-6264

    eISSN:2053-051X

    詳細を見る 詳細を閉じる

    The Subaru Deep Field (SDF) project is a program of Subaru Observatory to cam, out a deep galaxy survey over a blank field as large as 34' x 27'. The program consists of very deep multi-band optical imaging, near-infrared imaging for smaller portions of the field, and follow-up optical spectroscopy. The major scientific goals of the project are to construct large samples of Lyman-break galaxies at z similar or equal to 4-5 and Lyman alpha emitters at z similar or equal to 5.7 and 6.6, and to make detailed studies of these very high-redshift galaxy populations. In this paper. we describe, the-optical imaging observations and data reduction, presenting mosaicked images and object catalogs in seven bandpasses. The optical imaging was made through five broad-band filters. B, V. R i'. z'. and two narrow-band filters. NB816 (lambda(c) = 8150 Angstrom) and NB921 (lambda(c) = 9196 Angstrom) with almost 10 hour integrations for each band. The limiting magnitudes measured at 3sigma on a 2" aperture are B = 28.45, V =227.74, R = 27.80, i' = 27.43. z' = 26.62. NB816 = 26.63, and NB921 = 26.54 in the AB system. The object catalog constructed for each of the seven bands contains more than 101 objects. The galaxy number counts corrected for detection incompleteness and star-count contributions are found to be consistent with previous results in the literature. Mosaicked images and catalogs of all the bands have been made open to the public on 2004 October 1 oil the SDF project website.

  193. Near-infrared colors of hard X-ray-selected active galactic nuclei 査読有り

    C. Watanabe, K. Ohta, M. Akiyama, Y. Ueda

    Astrophysical Journal Letters 610 (1 I) 128-139 2004年

    DOI: 10.1086/392495  

  194. Lyman break galaxies at z ∼ 5: Rest-frame ultraviolet spectra 査読有り

    M. Ando, K. Ohta, I. Iwata, C. Watanabe, N. Tamura, M. Akiyama, K. Aoki

    Astrophysical Journal Letters 610 (2 I) 635-641 2004年

    DOI: 10.1086/421900  

  195. Cosmological evolution of the hard X-ray AGN luminosity function: Formation history of supermassive black holes 査読有り

    Y. Ueda, M. Akiyama, K. Ohta, T. Miyaji

    Progress of Theoretical Physics Supplement (155) 209-216 2004年

    出版者・発行元:Published for the Yukawa Institute for Theoretical Physics and the Physical Society of Japan

    DOI: 10.1143/PTPS.155.209  

    ISSN:0375-9687

    詳細を見る 詳細を閉じる

    The cosmological evolution of the hard X-ray luminosity function (HXLF) of Active Galactic Nuclei (AGN) is investigated in the 2-10 keV luminosity range of 10^<41.5> - 10^<46.5> erg s^<-1> as a function of redshift up to 3. From a combination of surveys conducted at photon energies above 2 keV with HEA01, ASCA and Chandra, we construct a highly complete (>96%) sample consisting of 247 AGNs over the wide flux range of 10^<-10> - 3.8 × 10^<-15> erg cm^<-2> s^<-1> (2-10 keV). We find that (i) the fraction of X-ray absorbed AGNs decreases with the intrinsic luminosity and (ii) the evolution of the HXLF of the whole AGNs (including both type-I and type-II AGNs) is best described with a luminosity dependent density evolution where the cutoff redshift increases with the luminosity. Our results directly constrain the evolution of AGNs that produce a major part of the hard X-ray background, thus solving its origin quantitatively. Based on these results, we discuss the formation history of supermassive black holes in galactic centers. The total accreted mass traced by the HXLF with an accretion mass-to-energy conversion factor of 0.1 is consistent with an estimate of SMBH mass density from the demography of galaxies in nearby universe.

  196. A Strong Ly-alpha Emitter at z = 6.33 in the Subaru Deep Field Selected as an i'-Dropout 査読有り

    Nagao, T, Taniguchi, Y, Kashikawa, N, Kodaira, K, Kaifu, N, Ando, H, Karoji, H, Ajiki, M, Akiyama, M, Aoki, K, Doi, M, Fujita, S. S, Furusawa, H, Hayashino, T, Iwamuro, F, Iye, M, Kobayashi, N, Kodama, T, Komiyama, Y, Matsuda, Y, Miyazaki, S, Mizumoto, Y, Morokuma, T, Motohara, K, Murayama, T, Nariai, K, Ohta, K, Okamura, S, Ouchi, M, Sasaki, T, Sato, Y, Sekiguchi, K, Shimasaku, K, Shioya, Y, Tamura, H, Tanaka, I, Umemura, M, Yamada, T, Yasuda, N, Yoshida, M

    The Astrophysical Journal 613 (1) L9-L12 2004年

    DOI: 10.1086/424965  

  197. Cosmological evolution of the hard X-ray active galactic nucleus luminosity function and the origin of the hard X-ray background 査読有り

    Y. Ueda, M. Akiyama, K. Ohta, T. Miyaji

    Astrophysical Journal Letters 598 (2) 886-908 2003年12月1日

    DOI: 10.1086/378940  

  198. Optical identification of the ASCA medium sensitivity survey in the northern sky: Nature of hard X-ray-selected luminous active galactic nuclei 査読有り

    M. Akiyama, Y. Ueda, K. Ohta, T. Takahashi, T. Yamada

    Astrophysical Journal, Supplement Series 148 (2) 275-315 2003年10月

    DOI: 10.1086/376441  

  199. The Discovery of Two Lyman-alpha Emitters beyond Redshift 6 in the Subaru Deep Field 査読有り

    Kodaira, K, Taniguchi, Y, Kashikawa, N, Kaifu, N, Ando, H, Karoji, H, Ajiki, M, Akiyama, M, Aoki, K, Doi, M, Fujita, S. S, Furusawa, H, Hayashino, T, Imanishi, M, Iwamuro, F, Iye, M, Kawabata, K. S, Kobayashi, N, Kodama, T, Komiyama, Y, Kosugi, G, Matsuda, Y, Miyazaki, S, Mizumoto, Y, Motohara, K, Murayama, T, Nagao, T, Nariai, K, Ohta, K, Ohyama, Y, Okamura, S, Ouchi, M, Sasaki, T, Sekiguchi, K, Shimasaku, K, Shioya, Y, Takata, T, Tamura, H, Terada, H, Umemura, M, Usuda, T, Yagi, M, Yamada, T, Yasuda, N, Yoshida, M

    Publications of the Astronomical Society of Japan 55 L17-L21 2003年4月25日

    DOI: 10.1093/pasj/55.2.l17  

    ISSN:2053-051X

  200. Optical identification of the ASCA Lynx Deep Survey: An association of quasi-stellar objects and a supercluster at z = 1.3? 査読有り

    K. Ohta, M. Akiyama, Y. Ueda, T. Yamada, K. Nakanishi, G.B. Dalton, Y. Ogasaka, T. Kii, K. Hayashida

    Astrophysical Journal Letters 598 (1 I) 210-215 2003年

    出版者・発行元:None

    DOI: 10.1086/378690  

    ISSN:0004-637X

    eISSN:1538-4357

  201. Lyman break galaxies at z ∼ 5: Luminosity function 査読有り

    I. Iwata, K. Ohta, N. Tamura, M. Ando, S. Wada, C. Watanabe, M. Akiyama, K. Aoki

    Publication of the Astronomical Society of Japan 55 (2) 415-432 2003年

    出版者・発行元:Astronomical Society of Japan

    ISSN:0004-6264

  202. The hard X-ray luminosity function from ASCA surveys 査読有り

    Y. Ueda, M. Akiyama, K. Ohta, T. Miyaji

    Astronomische Nachrichten 324 (1-2) 36-39 2003年

    DOI: 10.1002/asna.200310010  

  203. A candidate of a type 2 quasi-stellar object at z = 0.9: Large X-ray absorption with a strong broad Hα emission line 査読有り

    M. Akiyama, Y. Ueda, K. Ohta

    Astrophysical Journal Letters 567 (1) 42-49 2002年3月1日

    DOI: 10.1086/338422  

  204. Chandra observations and optical identification of hard X-ray sources discovered with ASCA 査読有り

    S. Watanabe, M. Akiyama, Y. Ueda, K. Ohta, R. Mushotzky, T. Takahashi, T. Yamada

    Publications of the Astronomical Society of Japan 54 (5) 683-694 2002年

    DOI: 10.1093/pasj/54.5.683  

    ISSN:0004-6264

  205. The ASCA medium sensitivity survey: Source catalog and optical identification 査読有り

    Y Ueda, M Akiyama, Y Ishisaki, K Makishima, R Mushotzky, T Ohashi, K Ohta, T Takahashi, S Watanabe, T Yamada

    NEW CENTURY OF X-RAY ASTRONOMY 251 494-495 2001年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

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    We report the current status of the ASCA Medium Sensitivity Survey (AMSS; or the GIS catalog project). The latest results from the optical identification program for a hard-band selected sample are presented.

  206. Chandra observations of hard x-ray sources discovered with ASCA 査読有り

    S Watanabe, T Takahashi, Y Ueda, Y Ishisaki, M Akiyama, T Yamada, K Ohta, R Mushotzky

    NEW CENTURY OF X-RAY ASTRONOMY 251 498-499 2001年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

  207. An extremely red nucleus in an absorbed QSO at z = 0.65 査読有り

    M. Akiyama, K. Ohta

    Publications of the Astronomical Society of Japan 53 (1) 63-67 2001年

    出版者・発行元:Astronomical Society of Japan

    DOI: 10.1093/pasj/53.1.63  

    ISSN:0004-6264

  208. Near-infrared observations of type 2 QSO at z = 0.9 査読有り

    K. Nakanishi, M. Akiyama, K. Ohta, T. Yamada

    Astrophysical Journal Letters 534 (2) 587-593 2000年5月10日

    出版者・発行元:None

    DOI: 10.1086/308789  

    ISSN:0004-637X

    eISSN:1538-4357

  209. Optical identification of the ASCA Large Sky Survey 査読有り

    M Akiyama, K Ohta, T Yamada, N Kashikawa, M Yagi, W Kawasaki, M Sakano, T Tsuru, Y Ueda, T Takahashi, Lehmann, I, G Hasinger, W Voges

    ASTROPHYSICAL JOURNAL 532 (2) 700-727 2000年4月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/308606  

    ISSN:0004-637X

    eISSN:1538-4357

    詳細を見る 詳細を閉じる

    We present results of optical identification of the X-ray sources detected in the ASCA Large Sky Survey. Optical spectroscopic observations were done for 34 X-ray sources that were detected with the SIS in the 2-7 keV band above 3.5 sigma. The flux limit corresponds to similar to 1 x 10(-13) ergs cm(-2) s(-1) in the 2-10 keV band. The sources are identified with 30 active galactic nuclei (AGNs), two clusters of galaxies, and one Galactic star. Only one source is still unidentified. All of the X-ray sources that have a hard X-ray spectrum with an apparent photon index of smaller than 1 in the 0.7-10 keV band are identified with narrow-line or weak-broad-line AGNs at redshifts smaller than 0.5. This fact supports the idea that absorbed X-ray spectra of narrow-line and weak-broadline AGNs make the cosmic X-ray background (CXB) spectrum harder in the hard X-ray band than that of a broad-line AGN, which is the main contributor in the soft X-ray band. Assuming their intrinsic spectra are same as a broad-line AGN (a power-law model with a photon index of 1.7), their X-ray spectra are fitted with hydrogen column densities of log N-H(cm(-2)) = 22-23 at the object's redshift. On the other hand, X-ray spectra of the other AGNs are consistent with that of a nearby type 1 Seyfert galaxy. In the sample, four high-redshift luminous broad-line AGNs show a hard X-ray spectrum with an apparent photon index of 1.3 +/- 0.3. The hardness may be explained by the reflection component of a type 1 Seyfert galaxy. The hard X-ray spectra may also be explained by absorption with log N-H(cm(-2)) = 22-23 at the object's redshift, if we assume an intrinsic photon index of 1.7. The origin of the hardness is not clear yet. Based on the log N-log S relations of each population, contributions to the CXB in the 2-10 keV band are estimated to be 9% for less-absorbed AGNs (log N-H(cm(-2)) &lt; 22) including the four high-redshift broad-line AGNs with a hard X-ray spectrum, 4% for absorbed AGNs (22 &lt; log N-H(cm(-2)) &lt; 23, without the four hard broad-line AGNs), and 1% for clusters of galaxies in the flux range from 3 x 10(-11) ergs cm(-2) s(-1) to 2 x 10(-13) ergs cm(-2) s(-1). If the four hard broad-line AGNs are included in the absorbed AGNs, the contribution of the absorbed AGNs to the CXB is estimated to be 6%. In optical spectra, there is no high-redshift luminous cousin of a narrow-line AGN in our sample. The redshift distribution of the absorbed AGNs is limited below z = 0.5 excluding the four hard broad-line AGNs, in contrast to the existence of 15 less-absorbed AGNs above z = 0.5. The redshift distribution of the absorbed AGNs suggests a deficiency of AGNs with column densities of log N-H(cm(-2))= 22-2-3 in the redshift range 0.5-2, or in the X-ray luminosity range larger than 10(44) ergs s(-1), or both. If the large column densities of the four hard broad-line AGNs are real, they could complement the deficiency of X-ray absorbed luminous high-redshift AGNs.

  210. Results from the ASCA Large Sky Survey - Nature of faint X-ray sources and the implications for the origin of the CXB

    Y Ueda, M Akiyama, G Hasinger, H Inoue, Y Ishisaki, K Makishima, Y Ogasaka, K Ohta, M Sakano, T Takahashi, T Tsuru, W Voges, T Yamada

    BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES 25 (3-4) 839-844 2000年

    出版者・発行元:PERGAMON PRESS LTD

    DOI: 10.1016/S0273-1177(99)00851-0  

    ISSN:0273-1177

    詳細を見る 詳細を閉じる

    We report results from the ASCA Large Sky Survey (LSS); the first wide-area unbiased survey in the 0.7-10 keV band over a continuous region of 7 deg(2) near the north Galactic pole. Applying the newly developed source-detection method to the LSS data independently ill the total (0.7-7 keV), hard (2-10 keV), and soft (0.7-2 keV) band, we detected 107 sources altogether with sensitivity limits of 6 x 10(-14) (0.7-7 keV), 1 x 10(-13) (2-10 keV), and 2 x 10(-14) erg s(-1) cm(-2) (0.7-2 keV), respectively. At these flux limits, 30(+/-3)% of the CXB in the 0.7-7 keV band and 23(+/-3)% in the 2-10 keV band have been resolved into discrete sources. The average spectrum of faint sources near the sensitivity limits show a photon index of 1.49+/-0.10 in the 2-10 keV range, and 1.63+/-0.07 ill the 0.7-10 keV range. These spectral properties suggest that contribution of sources with hard energy spectra become significant at a flux level of 10(-13) erg s(-1) cm(-2) (2-10 keV). Optical identification for a sample of 34 sources detected in the hard band revealed that at least six of them are type-2 AGNs. We found a good correlation that hard sources correspond to type-2 AGNs, while the photon index of type-1 AGNs is distributed around 1.6-1.8 in the 0.7-10 keV range. Follow-up X-ray observations of selected five hard-sources indicate that their spectra are subject to heavy absorption with an intrinsic hydrogen column density of 10(22) similar to 10(23) cm(-2). These results support the scenario that the CXB is the mixture of the emission fi om non-absorbed sour ces and absorbed soul ces. (C) 2000 COSPAR. Published by Elsevier Science Ltd.

  211. The First Light of the Subaru Telescope: A New Infrared Image of the Orion Nebula 査読有り

    Kaifu} Norio, Usuda} Tomonori, Hayashi, Saeko S, Itoh} Yoichi, Akiyama} Masayuki, Yamashita} Takuya, Nakajima} Yasushi, Tamura} Motohide, Inutsuka} Shuichiro, Hayashi} Masahiko, Maihara} Toshinori, Iwamuro} Fumihide, Motohara} Kentaro, Iwai} Jun'ich, Tanabe} Hirohisa, Taguchi} Tomoyuki, Hata} Ryuji, Terada} Hiroshi, Goto} Miwa, Ando} Hiroyasu, Aoki} Tetsuo, Chikada} Yoshihiro, Doi} Mamoru, Ebizuka} Noboru, Fukuda} Takeo, Hamabe} Masaru, Hasegawa} Tetsuo, Horaguchi} Toshihiro, Ichikawa, Shinichi, Ichikawa} Takashi, Imanishi} Masatoshi, Imi} Katsumi, Inata} Motoko, Isobe} Shuzo, Iye} Masanori, Kamata} Yukiko, Kanzawa} Tomio, Karoji} Hiroshi, Kashikawa} Nobunari, Kataza} Hirokazu, Kato} Taichi, Kobayashi} Naoto, Kobayashi} Yukiyasu, Kodaira} Keiichi, Kosugi} George, Kurakami} Tomio, Mikami} Yoshitaka, Miyama, Shoken M, Miyashita} Akihiko, Miyata, Takashi, Miyazaki} Satoshi, Mizumoto} Yoshihiko, Nakagiri} Masao, Nakajima} Koich, Nakamura} Kyoko, Nariai} Kyoji, Nishihara} Eiji, Nishikawa} Jun, Nishimura} Shiro, Nishimura} Tetsuo, Nishino} Tetsuo, Noguchi} Kunio, Noguchi} Takeshi, Noumaru} Junichi, Ogasawara} Ryusuke, Okada} Norio, Okita} Kiichi, Omata} Koji, Oshima} Norio, Otsubo} Masashi, Sasaki} Goro, Sasaki} Toshiyuki, Sekiguchi} Maki, Sekiguchi} Kazuhiro, Shelton} Ian, Simpson} Chris, Suto} Hiroshi, Takami} Hideki, Takata} Tadafumi, Takato} Naruhisa, Tanaka} Kyoko, Tanaka} Wataru, Tomono} Daigo, Torii} Yasuo, Waseda} Koichi, Watanabe} Junichi, Watanabe} Masaru, Yagi} Masafumi, Yamashita, Yasumasa, Yasuda} Naoki, Yoshida} Michitoshi, Yoshida} Shigeomi, Yutani} Masami

    \pasj 52 (1) 1-8 2000年

    出版者・発行元:Astronomical Society of Japan

    DOI: 10.1093/pasj/52.1.1  

    ISSN:0004-6264

  212. Subaru First-Light Deep Photometry of Galaxies in A 851 Field 査読有り

    Iye} Masanori, Iwamuro} Fumihide, Maihara} Toshinori, Miyazaki} Satoshi, Okamura} Sadanori, Shimasaku} Kazuhiro, Simpson} Chris, Akiyama} Masayuki, Ando} Hiroyasu, Aoki} Tetsuo, Aoki} Tsutomu, Chikada} Yoshihiro, Doi} Mamoru, Ebizuka} Noboru, Fukuda} Takeo, Furusawa} Hisanori, Goto} Miwa, Hamabe} Masaru, Hata} Ryuji, Hayashi} Masahiko, Hayashi, Saeko S, Horaguchi} Toshihiro, Ichikawa, Shinichi, Ichikawa} Takashi, Imanishi} Masatoshi, Imi} Katsumi, Inata} Motoko, Isobe} Shuzo, Itoh} Yoichi, Iwai} Junichi, Kaifu} Norio, Kamata} Yukiko, Kanzawa} Tomio, Karoji} Hiroshi, Kashikawa} Nobunari, Kato} Taichi, Kawasaki} Wataru, Kimura, Masahiko, Kobayashi} Naoto, Kobayashi} Yukiyasu, Kodaira} Keiichi, Komiyama} Yutaka, Kosugi} George, Kurakami} Tomio, Mikami} Yoshitaka, Miyashita} Akihiko, Miyata, Takashi, Mizumoto} Yoshihiko, Motohara} Kentaro, Nakagiri} Masao, Nakajima} Koich, Nakamura} Kyoko, Nakata} Fumiaki, Nariai} Kyoji, Nishihara} Eiji, Nishikawa} Jun, Nishimura} Shiro, Nishimura} Tetsuo, Nishino} Tetsuo, Noguchi} Kunio, Noguchi} Takeshi, Noumaru} Junichi, Ogasawara} Ryusuke, Okada} Norio, Okita} Kiichi, Omata} Koji, Oshima} Norio, Otsubo} Masashi, Oya} Shin, Sasaki} Goro, Sasaki} Toshiyuki, Sawada} Yasuhiro, Sekiguchi} Kazuhiro, Sekiguchi} Maki, Shelton} Ian, Suto} Hiroshi, Suzuki} Katsuyuki, Taguchi} Tomoyuki, Takami} Hideki, Takata} Tadafumi, Takato} Naruhisa, Tamura} Motohide, Tanabe} Hirohisa, Tanaka} Kyoko, Tanaka} Wataru, Terada} Hiroshi, Tomono} Daigo, Torii} Yasuo, Tsukamoto} Hiroyuki, Usuda} Tomonori, Watanabe} Junichi, Watanabe} Masaru, Yagi} Masafumi, Yamashita} Takuya, Yamashita, Yasumasa, Yasuda} Naoki, Yoshida} Michitoshi, Yoshida} Shigeomi, Yutani} Masami

    \pasj 52 (1) 9-23 2000年

    出版者・発行元:Astronomical Society of Japan

    DOI: 10.1093/pasj/52.1.9  

    ISSN:0004-6264

  213. Infrared Imaging of the Gravitational Lens PG 1115+080 with the Subaru Telescope 査読有り

    Iwamuro} Fumihide, Motohara} Kentaro, Maihara} Toshinori, Iwai} Jun'ichi, Tanabe} Hirohisa, Taguchi} Tomoyuki, Hata} Ryuji, Terada} Hiroshi, Goto} Miwa, Oya} Shin, Akiyama} Masayuki, Ando} Hiroyasu, Aoki} Tetsuo, Chikada} Yoshihiro, Doi} Mamoru, Fukuda} Takeo, Hamabe} Masaru, Hayashi} Masahiko, Hayashi, Saeko S, Horaguchi} Toshihiro, Ichikawa, Shinichi, Ichikawa} Takashi, Imanishi} Masatoshi, Imi} Katsumi, Inata} Motoko, Isobe} Shuzo, Itoh} Yoichi, Iye} Masanori, Kaifu} Norio, Kamata} Yukiko, Kanzawa} Tomio, Karoji} Hiroshi, Kashikawa} Nobunari, Kato} Taichi, Kobayashi} Naoto, Kobayashi} Yukiyasu, Kodaira} Keiichi, Kosugi} George, Kurakami} Tomio, Mikami} Yoshitaka, Miyashita} Akihiko, Miyata, Takashi, Miyazaki} Satoshi, Mizumoto} Yoshihiko, Nakagiri} Masao, Nakajima} Koich, Nakamura} Kyoko, Nariai} Kyoji, Nishihara} Eiji, Nishikawa} Jun, Nishimura} Shiro, Nishimura} Tetsuo, Nishino} Tetsuo, Noguchi} Kunio, Noguchi} Takeshi, Noumaru} Jun'ichi, Ogasawara} Ryusuke, Okada} Norio, Okita} Kiichi, Omata} Koji, Oshima} Norio, Otsubo} Masashi, Sasaki} Goro, Sasaki} Toshiyuki, Sekiguchi} Maki, Sekiguchi} Kazuhiro, Shelton} Ian, Simpson} Chris, Suto} Hiroshi, Takami} Hideki, Takata} Tadafumi, Takato} Naruhisa, Tamura} Motohide, Tanaka} Kyoko, Tanaka} Wataru, Tomono} Daigo, Torii} Yasuo, Usuda} Tomonori, Waseda} Koichi, Watanabe} Juni'chi, Watanabe} Masaru, Yagi} Masafumi, Yamashita} Takuya, Yamashita, Yasumasa, Yasuda} Naoki, Yoshida} Michitoshi, Yoshida} Shigeomi, Yutani} Masami

    \pasj 52 (1) 25-32 2000年

    出版者・発行元:Astronomical Society of Japan

    DOI: 10.1093/pasj/52.1.25  

    ISSN:0004-6264

  214. Deep-imaging observations of a candidate of an absorbed QSO at z = 0.653, AX J131831+3341 査読有り

    M. Akiyama, K. Ohta, N. Tamura, M. Doi, M. Kimura, Y. Komiyama, S. Miyazaki, F. Nakata, S. Okamura, M. Sekiguchi, K. Shimasaku, M. Yagi, M. Hamabe, M. Yoshida, T. Takata

    Publications of the Astronomical Society of Japan 52 (4) 577-584 2000年

    出版者・発行元:Astronomical Society of Japan

    ISSN:0004-6264

  215. The hardest X-ray source discovered in the ASCA Large Sky Survey : Implications to the cosmic X-ray background 査読有り

    M. Sakano, K. Koyama, T. Tsuru, H. Awaki, Y. Ueda, T. Takahashi, M. Akiyama, K. Ohta, T. Yamada

    Advances in Space Research 25 (3-4) 849-852 2000年

    出版者・発行元:None

    DOI: 10.1016/S0273-1177(99)00853-4  

    ISSN:0273-1177

  216. Log N-log S relations and spectral properties of sources from the ASCA large sky survey: Their implications for the origin of the cosmic x-ray background (CXB) 査読有り

    Y. Ueda, T. Takahashi, H. Inoue, T. Tsuru, M. Sakano, Y. Ishisaki, Y. Ogasaka, K. Makishima, T. Yamada, M. Akiyama, K. Ohta

    Astrophysical Journal Letters 518 (2) 656-671 1999年6月20日

    出版者・発行元:None

    DOI: 10.1086/307291  

    ISSN:0004-637X

    eISSN:1538-4357

  217. Near-infrared observations of a type-2 QSO at z=0.9

    K Nakanishi, M Akiyama, K Ohta, T Yamada

    GALAXY INTERACTIONS AT LOW AND HIGH REDSHIFT (186) 361-361 1999年

    出版者・発行元:KLUWER ACADEMIC PUBL

    ISSN:0074-1809

  218. CO observations of high-z objects

    K Ohta, K Nakanishi, M Akiyama, TT Takeuchi, T Yamada, Y Shioya, K Kohno, R Kawabe, N Kuno, N Nakai

    GALAXY INTERACTIONS AT LOW AND HIGH REDSHIFT (186) 362-362 1999年

    出版者・発行元:KLUWER ACADEMIC PUBL

    ISSN:0074-1809

  219. Nature of hard X-ray sources from optical identifications of the ASCA Large Sky Survey 査読有り

    M. Akiyama, K. Ohta, T. Yamada, Y. Ueda, T. Takahashi, M. Sakano, T. Tsuru, I. Lehmann, G. Hasinger

    Astronomische Nachrichten 320 (4-5) 255-256 1999年

    出版者・発行元:None

    DOI: 10.1002/1521-3994(199908)320:4/5<255::AID-ASNA255>3.0.CO;2-S  

    ISSN:0004-6337

  220. The hardest X-ray source in the ASCA large sky survey: Discovery of a new type 2 seyfert 査読有り

    M. Sakano, K. Koyama, T. Tsuru, H. Awaki, Y. Ueda, T. Takahashi, M. Akiyama, K. Ohta, T. Yamada

    Astrophysical Journal Letters 505 (1) 129-133 1998年9月20日

    出版者・発行元:None

    DOI: 10.1086/306158  

    ISSN:0004-637X

    eISSN:1538-4357

  221. Optical identification of the hardest X-ray source in the ASCA large sky survey 査読有り

    M. Akiyama, K. Ohta, T. Yamada, M. Eracleous, J.P. Halpern, N. Kashikawa, M. Yagi, W. Kawasaki, M. Sakano, T. Tsuru, Y. Ueda, T. Takahashi

    Astrophysical Journal Letters 500 (1) 173-180 1998年6月10日

    出版者・発行元:None

    DOI: 10.1086/305728  

    ISSN:0004-637X

    eISSN:1538-4357

  222. A population of faint galaxies that contribute to the cosmic X-ray background 査読有り

    Y. Ueda, T. Takahashi, H. Inoue, T. Tsuru, M. Sakano, Y. Ishisaki, Y. Ogasaka, K. Makishima, T. Yamada, K. Ohta, M. Akiyama

    Nature 391 (6670) 866-868 1998年2月26日

    DOI: 10.1038/36047  

  223. Optical follow-up observations of the ASCA Large Sky Survey 査読有り

    M Akiyama, K Ohta, T Yamada, Y Ueda, T Takahashi, M Sakano, T Tsuru, B Boyle

    HOT UNIVERSE (188) 465-466 1998年

    出版者・発行元:SPRINGER

    ISSN:0074-1809

  224. Sky surveys with ASCA - Large Sky Survey

    Y Ueda, T Takahashi, H Inoue, T Tsuru, M Sakano, K Ohta, M Akiyama, Y Ishisaki, Y Ogasaka, K Makishima, T Yamada

    ASTRONOMISCHE NACHRICHTEN 319 (1-2) 47-50 1998年

    出版者・発行元:WILEY-V C H VERLAG GMBH

    DOI: 10.1002/asna.2123190123  

    ISSN:0004-6337

    詳細を見る 詳細を閉じる

    We have carried out the first systematic wide-area survey around a Galactic pole region with the ASCA satellite in the 0.7-10 keV energy band (Large Sky Survey; LSS). The observed area amounts to 7 deg(2). To make the best use of ASCA capability, we have developed a new source-detection method where the complicated detector responses are fully taken into account. Applying this method to the entire LSS data independently in three energy bands (0.7-2 keV, 2-10 keV, and 0.7-7 keV), we detected 104 sources in total (4.5 sigma detection). The Log N - Log S relation and spectral properties of faint sources are presented.

  225. Optical follow-up observations of the ASCA Lynx deep survey 査読有り

    Ohta, K, Yamada, T, Akiyama, M, Nakanishi, K, Hayashida, K, Kii, T, Ogasaka, Y

    ASTRONOMISCHE NACHRICHTEN 319 (1-2) 71-71 1998年

    出版者・発行元:None

    DOI: 10.1002/asna.2123190135  

    ISSN:0004-6337

  226. Optical follow-up observations of the ASCA Large Sky Survey 査読有り

    Akiyama, M, Ohta, K, Yamada, T, Ueda, Y, Takahashi, T, Sakano, M, Tsuru, T, Boyle, B

    ASTRONOMISCHE NACHRICHTEN 319 (1-2) 63-63 1998年

    出版者・発行元:None

    DOI: 10.1002/asna.2123190127  

    ISSN:0004-6337

  227. Detection of molecular gas in the quasar BR1202-0725 at redshift z=4.69 査読有り

    K Ohta, T Yamada, K Nakanishi, K Kohno, M Akiyama, R Kawabe

    NATURE 382 (6590) 426-428 1996年8月

    出版者・発行元:MACMILLAN MAGAZINES LTD

    DOI: 10.1038/382426a0  

    ISSN:0028-0836

    詳細を見る 詳細を閉じる

    ALTHOUGH great efforts(1-8) have been made to locate molecular gas-the material out of which stars form-in the early Universe, there have been only two firm detections at high redshift. Both are gravitationally lensed objects at redshift z approximate to 2.5 (refs 9-14). Here we report the detection of CO emission from the radio-quite quasar BR1202 - 0725, which is at redshift z approximate to 4.69. From the observed CO luminosity, we estimate that almost 10(11) solar masses of molecular hydrogen are associated with the quasar; this is comparable to the stellar mass of a present-day luminous galaxy. Our results suggest that BR1202 - 0725 is a massive galaxy, in which the gas is largely concentrated in the central region, and that it is currently undergoing a large burst of star formation.

︎全件表示 ︎最初の5件までを表示

MISC 39

  1. すばる望遠鏡広帯域分光装置NINJA:装置概要

    東谷千比呂, 吉田道利, 守屋尭, 本原顕太郎, 尾崎忍夫, 柳澤顕史, 大野良人, 美濃和陽典, 早野裕, 小山佑世, 冨永望, 大内正己, 田中賢幸, 田中雅臣, 秋山正幸, 長尾透, 松岡良樹, 櫛引洸佑, 穂満星冴

    日本天文学会年会講演予稿集 2022 2022年

    ISSN:1347-0639

  2. すばる望遠鏡広帯域分光装置NINJA:科学目標

    守屋尭, 吉田道利, 東谷千比呂, 本原顕太郎, 尾崎忍夫, 柳澤顕史, 大野良人, 小山佑世, 冨永望, 大内正己, 美濃和陽典, 早野裕, 田中賢幸, 田中雅臣, 秋山正幸, 長尾透, 松岡良樹, 櫛引洸佑, 穂満星冴

    日本天文学会年会講演予稿集 2022 2022年

    ISSN:1347-0639

  3. TMT科学運用の検討

    青木和光, 岩田生, 臼田知史, 小山佑世, 冨永望, 古澤久徳, 安井千香子, 秋山正幸, 田村陽一, 成田憲保, 藤井通子

    日本天文学会年会講演予稿集 2021 2021年

    ISSN:1347-0639

  4. Spatially resolved stellar mass buildup and quenching in massive disk galaxies over the last 10 Gyr revealed with spatially resolved SED fitting

    Abdurro'uf, Masayuki Akiyama

    2019年2月20日

    詳細を見る 詳細を閉じる

    Despite decreasing cosmic star formation rate density over the last 10 Gyr, the stellar mass ($M_{*}$) buildups in galaxies were still progressing during this epoch. About 50\% of the current $M_{*}$ density in the universe was built over the last $\sim 8.7$ Gyr. In this research, we investigated the stellar mass buildup and quenching of spatially resolved regions within massive disk galaxies over the last 10 Gyr. We apply the spectral energy distribution (SED) fitting method to SEDs of sub-galactic regions in galaxies to derive the spatially resolved distributions of SFR and $M_{*}$ in the galaxies. This namely \textit{pixel-to-pixel SED fitting} method is applied to massive disk galaxies at $0.01<z<0.02$ and $0.8<z<1.8$. We found that massive disk galaxies tend to build their $M_{*}$ and quench their star formation progressively from the central region to the outskirts, i.e. \textit{inside-out} stellar mass buildup and quenching.

  5. HSCサーベイによる赤方偏移0.6‐3.0におけるAGN周辺銀河の特性

    白崎裕治, 秋山正幸, 長尾透, 鳥羽儀樹, 何晩秋, 大石雅寿, 水本好彦, 宮崎聡, 西澤淳, 臼田知史

    日本天文学会年会講演予稿集 2017 290 2017年8月20日

    ISSN:1347-0639

  6. 次世代超大型望遠鏡 TMT のための広視野多天体補償光学

    秋山 正幸, 大野 良人

    光学 44 (10) 396-398 2015年10月

    出版者・発行元:日本光学会

    ISSN:0389-6625

  7. ULTIMATE-SUBARU:概念設計報告

    早野裕, 岩田生, 大屋真, 美濃和陽典, 児玉忠恭, LAI Olivier, 高見英樹, 寺田宏, 臼田知史, 西村徹郎, 家正則, 服部雅之, 服部尭, 友野大悟, 田中壱, 瀧浦晃基, 高遠徳尚, 大橋永芳, 有本信雄, 秋山正幸, 大野良人, 本原顕太郎, 渡辺誠, 山室智康

    日本天文学会年会講演予稿集 2013 2013年

    ISSN:1347-0639

  8. 近赤外線多天体分光の現在と将来

    秋山 正幸

    光技術コンタクト 2012年4月

  9. すばる次世代広視野補償光学および赤外線新装置:初期検討報告

    早野裕, 岩田生, 大屋真, 美濃和陽典, 児玉忠恭, 高見英樹, 寺田宏, 臼田知史, 西村徹郎, 家正則, 服部雅之, 服部尭, 友野大悟, 田中壱, 瀧浦晃基, 高遠徳尚, 大橋永芳, 有本信雄, 秋山正幸, 大野良人, 本原顕太郎, 田村直之, 渡辺誠, 山室智康

    日本天文学会年会講演予稿集 2012 2012年

    ISSN:1347-0639

  10. Stellar-Mass Metallicity Relation at z ~ 1.4

    K.Ohta, K.Yabe, F.Iwamuro, S.Yuma, M.Akiyama, N.Tamura, FMOS Team

    Galactic Archaeology: Near-Field Cosmology and the Formation of the Milky Way, volume 458 of Astronomical Society of the Pacic Conference Series, page 87 (2012), 08 2012年

  11. Subaru FMOS now and future 査読有り

    Naoyuki Tamura, Naruhisa Takato, Fumihide Iwamuro, Masayuki Akiyama, Masahiko Kimura, Philip Tait, Gavin B. Dalton, Graham J. Murray, Scott Smedley, Toshinori Maihara, Kouji Ohta, Yuuki Moritani, Kiyoto Yabe, Masanao Sumiyoshi, Tomonori Totani, Hajime Sugai, Hiroshi Karoji, Shiang-Yu Wang, Youichi Ohyama

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY IV 8446 2012年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.925831  

    ISSN:0277-786X

    詳細を見る 詳細を閉じる

    Fiber Multi Object Spectrograph "FMOS" on Subaru Telescope is capable of configuring 400 fibers on the 30-arcmin diameter field of view at the prime focus for near-infrared (0.9-1.8 mu m) spectroscopy, and this instrument has been open as a common-use instrument since May 2010. In this article, an overview of the instrument is given first, and then the typical operational sequence in science observation and a few notable features of the instrument are explained. In 5, the instrument performance in terms of fiber positioning, auto guiding, and sensitivity to emission lines are highlighted. Recently (since March 2012) a Subaru Strategic Program (SSP) has started with FMOS to conduct a wide-field galaxy survey for a cosmological experiment. Upgrading fiber configuration by using a "metrology camera" has also been under discussion, which will enable to measure the positions of the 400 fibers quickly and shorten the fiber configuration time significantly. We will also report the status of these recent activities.

  12. UNVEILING THE NATURE OF SUBMILLIMETER GALAXY SXDF 850.6 (vol 711, pg 974, 2010)

    B. Hatsukade, D. Iono, T. Yoshikawa, M. Akiyama, J. S. Dunlop, R. J. Ivison, A. B. Peck, S. Ikarashi, A. Biggs, H. Ezawa, H. Hanami, P. Ho, D. H. Hughes, R. Kawabe, K. Kohno, S. Matsushita, K. Nakanishi, N. Padilla, G. Petitpas, Y. Tamura, J. Wagg, D. J. Wilner, G. W. Wilson, T. Yamada, M. S. Yun

    ASTROPHYSICAL JOURNAL 716 (1) 891-891 2010年6月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1088/0004-637X/716/1/891  

    ISSN:0004-637X

  13. すばる望遠鏡・TMT望遠鏡での補償光学系

    高見英樹, 家正則, 山下卓也, 臼田知史, 柏川伸成, 青木和光, 秋田谷洋, 大島紀夫, 早野裕, 大屋真, 服部雅之, 斉藤嘉彦, 伊藤周, 美濃和陽典, 渡辺誠, 秋山正幸

    光学シンポジウム講演予稿集 35th 2010年

  14. FMOS the fibre multiple-object spectrograph, part VIII: current performances and results of the engineering observations 査読有り

    Masahiko Kimura, Masayuki Akiyama, Gavin B. Dalton, Fumihide Iwamuro, Ian J. Lewis, Toshinori Maihara, Kouji Ohta, Philip Tait, Naruhisa Takato, Naoyuki Tamura, Ian A. J. Tosh, Scott Smedley, Emma Curtis Lake, Takeshi Inagaki, Eric Jeschke, Kaori Kawate, Yuuki Moritani, Masanao Sumiyoshi, Kiyoto Yabe

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY III 7735 (PART 1) 2010年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.857416  

    ISSN:0277-786X

    eISSN:1996-756X

    詳細を見る 詳細を閉じる

    The Fibre Multi-Object Spectrograph for Subaru Telescope (FMOS) is a near-infrared instrument with 400 fibres in a 30' filed of view at F/2 prime focus. To observe 400 objects simultaneously, we have developed a fibre positioner called "Echidna" using a tube piezo actuator. We have also developed two OH-airglow suppressed and refrigerated spectrographs. Each spectrograph has two spectral resolution modes: the low-resolution mode and the high-resolution mode. The low-resolution mode covers the complete wavelength range of 0.9 - 1.8 mu m with one exposure, while the high-resolution mode requires four exposures at different camera positions to cover the full wavelength range. The first light was accomplished in May 2008. The science observations and the open-use observations begin in May 2010.

  15. The Subaru/XMM-Newton Deep Survey (SXDS). IV. Evolution of Ly alpha emitters from z=3.1 to 5.7 in the 1 deg(2) field: Luminosity functions and AGN

    Masami Ouchi, Kazuhiro Shimasaku, Masayuki Akiyama, Chris Simpson, Tomoki Saito, Yoshihiro Ueda, Hisanori Furusawa, Kazuhiro Sekiguchi, Toru Yamada, Tadayuki Kodama, Nobunari Kashikawa, Sadanori Okamura, Masanori Iye, Tadafumi Takata, Michitoshi Yoshida, Makiko Yoshida

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 176 (2) 301-330 2008年6月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/527673  

    ISSN:0067-0049

    eISSN:1538-4365

    詳細を見る 詳細を閉じる

    We present luminosity functions (LFs) and various properties of Ly alpha emitters (LAEs) at z = 3.1, 3.7, and 5.7, in a 1 deg(2) sky of the Subaru/XMM-Newton Deep Survey (SXDS) Field. We obtain a photometric sample of 858 LAE candidates based on deep Subaru Suprime-Cam imaging data and a spectroscopic sample of 84 confirmed LAEs from Subaru FOCAS and VLT VIMOS spectroscopy in a survey volume of similar to 10(6) Mpc(3) with a limiting Ly alpha luminosity of similar to 3 x 10(42) ergs s(-1). We derive the LFs of the Ly alpha andUV continuum (similar or equal to 1500 angstrom) for each redshift, taking into account the statistical error and the field-to-field variation. We find that the apparent Ly alpha LF shows no significant evolution between z = 3.1 and 5.7 within factors of 1.8 and 2.7 in L* and phi*, respectively. On the other hand, the UV LF of LAEs increases from z 3: 1 to 5.7, indicating that galaxies with Ly alpha emission are more common at earlier epochs. We identify six LAEs with AGN activities from our spectra combined with VLA, Spitzer, and XMM-Newton data. Among the photometrically selected LAEs at z = 3.1 and 3.7, only similar or equal to 1% show AGN activities, while the brightest LAEs with log L(Ly alpha) greater than or similar to 43.4 43.6 ergs s(-1) appear to always host AGNs. Our LAEs are bluer in UV-continuum color than dropout galaxies, suggesting lower extinction and/or younger stellar populations. Our stacking analyses provide upper limits to the radio luminosity and the f(He) (II)/f(Ly alpha) line fraction and constrain the hidden star formation (+ low-luminosity AGN) and the primordial population in LAEs.

  16. The Subaru/XMM-Newton deep survey (SXDS). II. Optical imaging and photometric catalogs

    Hisanori Furusawa, George Kosugi, Masayuki Akiyama, Tadafumi Takata, Kazuhiro Sekiguchi, Ichi Tanaka, Ikuru Iwata, Masaru Kajisawa, Naoki Yasuda, Mamoru Doi, Masami Ouchi, Chris Simpson, Kazuhiro Shimasaku, Toru Yamada, Junko Furusawa, Tomoki Morokuma, Catherine M. Ishida, Kentaro Aoki, Tetsuharu Fuse, Masatoshi Imanishi, Masanori Iye, Hiroshi Karoji, Naoto Kobayashi, Tadayuki Kodama, Yutaka Komiyama, Yoshitomo Maeda, Satoshi Miyazaki, Yoshihiko Mizumoto, Fumiaki Nakata, Jun'ichi Noumaru, Ryusuke Ogasawara, Sadanori Okamura, Tomoki Saito, Toshiyuki Sasaki, Yoshihiro Ueda, Michitoshi Yoshida

    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 176 (1) 1-18 2008年5月

    出版者・発行元:IOP PUBLISHING LTD

    DOI: 10.1086/527321  

    ISSN:0067-0049

    eISSN:1538-4365

    詳細を見る 詳細を閉じる

    We present multi-wave band optical imaging data obtained from observations of the Subaru/XMM-Newton Deep Survey (SXDS). The survey field, centered at R.A. = 02(h)18(m)00(s), decl. = -05 degrees 00'00 '', has been the focus of a wide range of multiwavelength observing programs spanning from X-ray to radio wavelengths. A large part of the optical imaging observations are carried out with Suprime-Cam on Subaru Telescope at Mauna Kea in the course of Subaru Telescope "Observatory Projects.'' This paper describes our optical observations, data reduction and analysis procedures employed, and the characteristics of the data products. A total area of 1.22 deg(2) is covered in five contiguous subfields, each of which corresponds to a single Suprime-Cam field of view (similar to 34' x 27'), in five broadband filters, B, V, R-c, i', and z', to the depths of B = 28.4, V = 27.8, R-c = 27.7, z' = 27.7, and z' = 26.6, respectively (AB, 3 sigma, phi = 2 ''). The data are reduced and compiled into five multiwave band photometric catalogs, separately for each Suprime-Cam pointing. The i'-band catalogs contain about 900,000 objects, making the SXDS catalogs one of the largest multi-wave band catalogs in corresponding depth and area coverage. The SXDS catalogs can be used for an extensive range of astronomical applications such as the number density of the Galactic halo stars to the large-scale structures at the distant universe. The number counts of galaxies are derived and compared with those of existing deep extragalactic surveys. The optical data, the source catalogs, and configuration files used to create the catalogs are publicly available via the SXDS Web page (http://www. naoj. org/Science/SubaruProject/SXDS/index. html).

  17. A Morphological Study of Luminous Infrared Galaxies at Redshift z similar to 1 in the MOIRCS Deep Survey

    M. Konishi, R. Suzuki, C. Tokoku, Y. K. Uchimoto, T. Yoshikawa, T. Ichikawa, I. Tanaka, M. Akiyama, M. Kajisawa, M. Ouchi, K. Omata, T. Nishimura, T. Yamada

    PANORAMIC VIEWS OF GALAXY FORMATION AND EVOLUTION, PROCEEDINGS 399 211-213 2008年

    出版者・発行元:ASTRONOMICAL SOC PACIFIC

  18. FMOS: the fiber multiple-object spectrograph VI: on board performances and results of the engineering observations 査読有り

    Fumihide Iwamuro, Toshinori Maihara, Masayuki Akiyama, Masahiko Kimura-, Naoyuki Tamura, Naruhisa Takato, Philip Tait, Kouji Ohta, Shigeru Eto, Yuuki Moritani, Gavin B. Dalton, Ian J. Lewis, Hanshin Lee, Ian A. J. Tosh, Tim R. Froud, Graham J. Murray, Colin Blackburn, David G. Bonfield, Peter R. Gillingham, Scott Smedley, Greg A. Smith, Gabriella Frost

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY II, PTS 1-4 7014 2008年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.787746  

    ISSN:0277-786X

    eISSN:1996-756X

    詳細を見る 詳細を閉じる

    FMOS: the Fiber Multiple-Object Spectrograph is the next common-use instrument of the Subaru Telescope, having a capability of 400 targets multiplicity in the near-infrared 0.9-1.8 mu m wavelength range with a field coverage of 30' diameter. FMOS consists of three units: 1) the prime focus unit including the corrector lenses, the Echidna fiber positioner, and the instrument-bay to adjest the instrument focus and shift the axis off the corrector lens system, 2) the fiber bundle unit equipping two fiber slits on one end and a fiber connector box with the back-illumination mechanism on the other end of the bundle, 3) the two infrared spectrographs (IRS1 and IRS2) to obtain 2x200 spectra simultaneously. After all the components were installed in the telescope at the end of 2007, the total performance was checked through various tests and engineering observations. We report the results of these tests and demonstrate the performance of FMOS.

  19. FMOS: The Fibre Multi-Object Spectrograph VII Results of PIR engineering run 査読有り

    Masahiko Kimura, Toshinori Maihara, Fumihide Iwamuro, Masayuki Akiyama, Naoyuki Tamura, Naruhisa Takato, Kouji Ohta, Shigeru Eto

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY II, PTS 1-4 7014 2008年

    出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING

    DOI: 10.1117/12.790252  

    ISSN:0277-786X

    eISSN:1996-756X

    詳細を見る 詳細を閉じる

    Fibre Multi-Object Spectrograph (FMOS) is the next common-use instrument of Subaru Telescope. FMOS consists of three subsystems; the Prime focus unit for Infrared (PIR), the fibre positioning system/connector units, and the two infrared spectrographs. The PIR was transferred to the Subaru Observatory in the spring of 2005 to check the optical performance on the telescope. As a result of the test observation, we found that the adjustment of the optical axis between PIR and the primary mirror was difficult with the initial design of the corrector alignment stage. Furthermore, the optical axis of the telescope moved over a little owing to an earthquake in Hawaii Island in Oct. 2006. Therefore we decided to modify mechanical structure of PIR, the corrector alignment stage as well as the cable wrapping system. This modification was completed in the summer of 2007. In this proceeding, we report the mechanical structure of the new PIR and the results of the engineering observations.

  20. Rest-Optical Spectroscopic Properties of Luminous Infrared Galaxies at z~2

    Yoshikawa, T, Akiyama, M, Ichikawa, T

    Panoramic Views of Galaxy Formation and Evolution ASP Conference Series 399 214-215 2008年

  21. Adaptive optics imaging of Lyman break galaxies as progenitors of spheroids in the local Universe 査読有り

    M. Akiyama, Y. Minowa, N. Kobayashi, K. Ohta, I. Iwata

    Proceedings of the International Astronomical Union 3 (S245) 447-450 2007年

    DOI: 10.1017/S1743921308018334  

  22. The Long Faint Tail of the High-Redshift Galaxy Population

    Marcin Sawicki, Ikuru Iwata, Kouji Ohta, David Thompson, Naoyuki Tamura, Masayuki Akiyama, Kentaro Aoki, Masataka Ando, Gaku Kiuchi

    2006年12月5日

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    We study the properties of very faint, sub-L* Lyman break galaxies at z~2-5 - thus far a largely neglected but numerically and energetically very important population. We find that the LBG luminosity function undergoes luminosity-dependent evolution: the number of luminous galaxies remains constant while the number of faint ones grows with time. The total UV luminosity density increases with cosmic time from at least z~5 until reaching a peak or a plateau around z~2 - behaviour that is governed by the sub-L* galaxies in the LF's "faint tail". Using broadband SED fitting we find a nearly-linear relationship between SFR and galaxy stellar mass at z~2. A typical L* LBG at z~2 shows a stellar mass of ~10^10M_sun, remarkably similar to the bimodality mass at low redshift. This similarity suggests that the mechanisms responsible for the galaxy bimodality at low-z may have also been at play at z~2.

  23. MOIRCS Deep Survey. I: DRG number counts

    Masaru Kajisawa, Masahiro Konishi, Ryuji Suzuki, Chihiro Tokoku, Yuka Katsuno Uchimoto, Tomohiro Yoshikawa, Masayuki Akiyama, Takashi Ichikawa, Masami Ouchi, Koji Omata, Ichi Tanaka, Tetsuo Nishimura, Toru Yamada

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 58 (6) 951-956 2006年12月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/58.6.951  

    ISSN:0004-6264

    eISSN:2053-051X

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    We used very deep near-infrared imaging data taken with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru Telescope to investigate the number Counts of Distant Red Galaxies (DRGs). We observed a 4' x 7' field in the Great Observatories Origins Deep Survey-North (GOODS-N), and our data reached J = 24.6 and K = 23.2 (5 sigma, Vega magnitude). The surface density of DRGs selected by J - K > 2.3 is 2.35 +/- 0.31 arcmin(-2) at K < 22 and 3.54 +/- 0.38 arcinin(-2) at K < 23, respectively. These values are consistent with those in the GOODS-South and FIRES. Our deep and wide data Suggest that the number counts of DRGs turn over at K - 22, and the surface density of the faint DRGs with K > 22 is smaller than that expected from the number counts at the brighter magnitude. The result indicates that while there are many bright galaxies at 2 < z < 4 with the relatively old stellar Population and/or heavy dust extinction, the number of faint galaxies with a similar red color is relatively small. Different behavior patterns of the number counts of the DRGs and bluer galaxies with 2 < z(phot) < 4 at K > 22 suggest that the mass-dependent color distribution, where most of the low-inass galaxies are blue, while more massive galaxies tend to have redder colors, had already been established at that epoch.

  24. Radio imaging of the Subaru/XMM-Newton Deep Field - I. The 100-mu Jy catalogue, optical identifications, and the nature of the faint radio source population

    Chris Simpson, Alejo Martinez-Sansigre, Steve Rawlings, Rob Ivison, Masayuki Akiyama, Kazuhiro Sekiguchi, Tadafumi Takata, Yoshihiro Ueda, Mike Watson

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 372 (2) 741-757 2006年10月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1111/j.1365-2966.2006.10907.x  

    ISSN:0035-8711

    eISSN:1365-2966

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    We describe deep radio imaging at 1.4 GHz of the 1.3-deg(2) Subaru/XMM-Newton Deep Field (SXDF), made with the Very Large Array in B and C configurations. We present a radio map of the entire field, and a catalogue of 505 sources covering 0.8 deg(2) to a peak flux density limit of 100 mu Jy. Robust optical identifications are provided for 90 per cent of the sources, and suggested identifications are presented for all but 14 (of which seven are optically blank, and seven are close to bright contaminating objects). We show that the optical properties of the radio sources do not change with flux density, suggesting that active galactic nuclei (AGN) continue to contribute significantly at faint flux densities. We test this assertion by cross-correlating our radio catalogue with the X-ray source catalogue and conclude that radio-quiet AGN become a significant population at flux densities below 300 mu Jy, and may dominate the population responsible for the flattening of the radio source counts if a significant fraction of them are Compton-thick.

  25. Luminosity dependent evolution of lyman break galaxies from redshift 5 to 3 査読有り

    I. Iwata, K. Ohta, N. Tamura, M. Akiyama, K. Aoki, M. Ando, G. Kiuchi, M. Sawicki

    Proceedings of the International Astronomical Union 2 (S235) 364-365 2006年

    DOI: 10.1017/S1743921306010179  

  26. Host Galaxies of the High-redshift AGNs in the GOODS Fields

    Masayuki Akiyama

    2005年5月16日

    DOI: 10.1086/431291  

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    The star-formation rates and the stellar masses of the host galaxies of AGNs at high-redshifts are keys to understanding the evolution of the relation between the mass of the spheroidal component of a galaxy and the mass of its central black hole. We investigate the host galaxies of 31 AGNs with spectroscopic redshifts between 2 and 4 found in the deep Chandra surveys of the GOODS fields with the ACS images. The sample can be divided into 17 ``extended'' AGNs and 14 ``compact'' AGNs based on the concentration parameter defined as the difference between the aperture magnitudes with 0.07" and 0.25" diameter. We derive upper limits of the UV luminosities of the host galaxies of the ``compact'' AGN sample, and upper and lower limits of the UV luminosities of the host galaxies of the ``extended'' AGN sample.These limits are consistent with the knee of the luminosity function of the Lyman Break Galaxies (LBGs) at z=3, suggesting moderate star-formation rates, less than 40 Msolar/yr, in the host galaxies of the AGNs at 2<z_sp<4 without correcting the dust extinction. By combining the limits of the UV luminosities with the observed K-band magnitudes for the ``extended'' AGNs, we derive the upper and lower limits of the stellar masses of their host galaxies. The derived upper limits on the stellar masses range from 10^10 Msolar to 10^12 Msolar. The upper limits imply that the Mbulge-MBH relation of the high-redshift AGNs is different from that of the galaxies in the nearby universe or the average Eddington ratio of the high-redshift AGNs is higher than that of low-redshift AGNs with lower-luminosity.

  27. Down-sizing in galaxy formation at z similar to 1 in the Subaru/XMM-Newton Deep Survey (SXDS)

    T Kodama, T Yamada, M Akiyama, K Aoki, M Doi, H Furusawa, T Fuse, M Imanishi, C Ishida, M Iye, M Kajisawa, H Karoji, N Kobayashi, Y Komiyama, G Kosugi, Y Maeda, S Miyazaki, Y Mizumoto, T Morokuma, F Nakata, J Noumaru, R Ogasawara, M Ouchi, T Sasaki, K Sekiguchi, K Shimasaku, C Simpson, T Takata, Tanaka, I, Y Ueda, N Yasuda, M Yoshida

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 350 (3) 1005-1014 2004年5月

    出版者・発行元:WILEY-BLACKWELL

    DOI: 10.1111/j.1365-2966.2004.07711.x  

    ISSN:0035-8711

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    We use the deep wide-field optical imaging data of the Subaru/XMM-Newton Deep Survey to discuss the luminosity- (mass-)dependent galaxy colours down to z&apos; = 25.0 (5 x 10(9) h(70)(-2) M(circle dot)) for z similar to 1 galaxies in colour-selected high-density regions. We find an apparent absence of galaxies on the red colour-magnitude sequence below z&apos; similar to 24.2, corresponding to similar toM* + 2 (similar to 10(10) M(circle dot)) with respect to passively evolving galaxies at z similar to 1. Galaxies brighter than M* - 0.5 (8 x 10(10) M(circle dot)), however, are predominantly red passively evolving systems, with few blue star-forming galaxies at these magnitudes. This apparent age gradient, where massive galaxies are dominated by old stellar populations while less massive galaxies have more extended star formation histories, supports the &apos;down-sizing&apos; idea where the mass of galaxies hosting star formation decreases as the Universe ages. Combined with the lack of evolution in the shape of the stellar mass function for massive galaxies since at least z similar to 1, it appears that galaxy formation processes (both star formation and mass assembly) should have occurred in an accelerated way in massive systems in high-density regions, while these processes should have been slower in smaller systems. This result provides an interesting challenge for modem cold dark matter based galaxy formation theories which predict later formation epochs of massive systems, commonly referred to as &apos;bottom-up&apos;.

  28. The fiber multi-object spectrograph (FMOS) for the Subaru Telescope III 査読有り

    S. Eto, T. Maihara, K. Ohta, F. Iwamuro, M. Kimura, D. Mochida, S. Wada, S. Imai, Y. Narita, Y. Nakajima, H. Karoji, J. Noumaru, M. Akiyama, P. Gillingham, S. Smedley, N. Tamura

    Proceedings of SPIE - The International Society for Optical Engineering 5492 (PART 3) 1314-1318 2004年

    DOI: 10.1117/12.551087  

  29. XMM-Newton observations reveal AGN in apparently normal galaxies

    P Severgnini, A Caccianiga, Braito, V, R Della Ceca, T Maccacaro, A Wolter, K Sekiguchi, T Sasaki, M Yoshida, M Akiyama, MG Watson, Barcons, X, FJ Carrera, W Pietsch, NA Webb

    ASTRONOMY & ASTROPHYSICS 406 (2) 483-492 2003年8月

    出版者・発行元:EDP SCIENCES S A

    DOI: 10.1051/0004-6361:20030625  

    ISSN:0004-6361

    eISSN:1432-0746

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    We have performed a detailed analysis of 3 optically normal galaxies extracted from the XMM Bright Serendipitous Source Sample. Thanks to the good statistics of the XMM-Newton data, we have unveiled the presence of an AGN in all of them. In particular, we detect both X-ray obscured (N-H &gt; 10(22) cm(-2)) and unobscured (N-H &lt; 10(22) cm(-2)) AGNs with intrinsic 2-10 keV luminosities in the range between 10(42)-10(43) erg s(-1). We find that the X-ray and optical properties of the sources discussed here could be explained assuming a standard AGN hosted by galaxies with magnitudes M-R &lt; M*, taking properly into account the absorption associated with the AGN, the optical faintness of the nuclear emission with respect to the host galaxy, and the inadequate set-up and atmospheric conditions during the optical spectroscopic observations. Our new spectroscopic observations have revealed the expected AGN features also in the optical band. These results clearly show that optical spectroscopy sometimes can be inefficient in revealing the presence of an AGN, which instead is clearly found from an X-ray spectroscopic investigation. This remarks the importance of being careful in proposing the identification of X-ray sources (especially at faint fluxes) when only low quality optical spectra are in hand. This is particularly important for faint surveys (such as those with XMM-Newton and Chandra), in which optically dull but X-ray active objects are being found in sizeable numbers.

  30. The discovery of two Lyman alpha emitters beyond redshift 6 in the Subaru Deep Field

    K Kodaira, Y Taniguchi, N Kashikawa, N Kaifu, H Ando, H Karoji, M Ajiki, M Akiyama, K Aoki, M Doi, SS Fujita, H Furusawa, T Hayashino, M Imanishi, F Iwamuro, M Iye, KS Kawabata, N Kobayashi, T Kodama, Y Komiyama, G Kosugi, Y Matsuda, S Miyazaki, Y Mizumoto, K Motohara, T Murayama, T Nagao, K Nariai, K Ohta, Y Ohyama, S Okamura, M Ouchi, T Sasaki, K Sekiguchi, K Shimasaku, Y Shioya, T Takata, H Tamura, H Terada, M Umemura, T Usuda, M Yagi, T Yamada, N Yasuda, M Yoshida

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 55 (2) L17-L21 2003年4月

    出版者・発行元:OXFORD UNIV PRESS

    DOI: 10.1093/pasj/55.2.L17  

    ISSN:0004-6264

    eISSN:2053-051X

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    We performed a deep optical imaging survey using a narrow-band filter (NB921) centered at lambda = 9196 (A) over circle together with i' and z' broadband filters covering an 814arcmin(2) area of the Subaru Deep Field. We obtained a sample of 73 strong NB 921 -excess objects based on the following two color criteria: z' - NB 921 &gt; 1 and i' - z' &gt; 1.3. We then obtained optical spectroscopy of nine objects in our NB 92 1 -excess sample, and identified at least two Ly a emitters at z = 6.541 +/- 0.002 and z = 6.578 +/- 0.002, each of which shows the characteristic sharp cutoff together with continuum depression at wavelengths shortward of the line peak. The latter object is more distant than HCM-6A at z = 6.56, which is the most distant known object that has been found so far. These new data allow us to estimate the first meaningful lower limit of the star-formation rate density beyond redshift 6; rho(SFR) similar to 5.2 x 10(-4) M-circle dot yr(-1) Mpc(-3). Since it is expected that the actual density is several times higher than this value, our new observation reveals that a moderately high level of star formation activity already occurred at z similar to 6.6.

  31. 宇宙X線背景放射と隠された活動銀河中心核 : 「あすか」衛星によるサーベイから得られた結果を中心として

    秋山 正幸, 上田 佳宏, 太田 耕司

    天文月報 96 (3) 119-130 2003年2月20日

    出版者・発行元:日本天文学会

    ISSN:0374-2466

  32. AGN Populations from Optical Identification of ASCA Surveys

    Masayuki Akiyama, Yoshihiro Ueda, Kouji Ohta

    2002年1月30日

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    To understand luminous AGNs in the z<1 universe, the ASCA AGN samples are the best at present. Combining the identified sample of AGNs from ASCA Large Sky Survey and Medium Sensitivity Survey, the sample of hard X-ray selected AGNs have been expanded up to 108 AGNs above the flux limit of 10^{-13} erg s^{-1} cm^{-2} in the 2-10 keV hard X-ray band. We discuss the fraction of absorbed AGNs in the hard X-ray selected AGN sample, and nature of absorbed luminous AGNs.

  33. Fibre-Multi-Object Spectrograph (FMOS) for Subaru telescope 査読有り

    M. Kimura, T. Maihara, K. Ohta, F. Iwamuro, S. Eto, M. Iino, D. Mochida, T. Shima, H. Karoji, J. Noumaru, M. Akiyama, J. Brezeski, P. Gillingham, A. Moore, G. Smith, G.B. Dalton, I. Tosh, G. Murray, D. Robertson, N. Tamura

    Proceedings of SPIE - The International Society for Optical Engineering 4841 (2) 974-984 2002年

    DOI: 10.1117/12.461208  

  34. AGN Population at 10^-13 erg s-1 cm-2: Results from Optical Identification of ASCA Surveys

    Masayuki Akiyama

    2001年1月4日

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    In this paper, results of optical identification of ASCA surveys are summarized. To understand luminous AGNs in the z<1 universe, the ASCA AGN sample is still better than samples of AGNs from deep Chandra or XMM-Newton surveys. Combining the identified sample of AGNs from ASCA Large Sky Survey and Medium Sensitivity Survey, the sample of hard X-ray selected AGNs have been expanded up to about 80 AGNs above the flux limit of 10^{-13} erg s^{-1} cm^{-2} in the 2-10keV band. One fifth of the ASCA AGNs are absorbed narrow-line AGNs. The luminosity distribution of the absorbed AGNs is limited below 10^{45} erg s^{-1}, though there are 14 non-absorbed broad-line AGNs are detected above the luminosity. The result suggests lack of absorbed luminous AGNs (deficiency of type 2 QSO).

  35. CO(J=2-1)Observations of the Quasar BR 1202-0725 at z=4.7

    Ohta Kouji, Nakanishi Kouichiro, Akiyama Masayuki, YAMADA Toru, KOHNO Kotaro, KAWABE Ryohei, KUNO Nario, NAKAI Naomasa

    PASJ : publications of the Astronomical Society of Japan 50 (3) 303-308 1998年6月25日

    出版者・発行元:Astronomical Society of Japan

    ISSN:0004-6264

  36. Optical follow-up observations of ASCA Lynx deep survey 査読有り

    K Ohta, M Akiyama, K Nakanishi, T Yamada, K Hayashida, T Kii, Y Ogasaka

    HOT UNIVERSE (188) 471-472 1998年

    出版者・発行元:KLUWER ACADEMIC PUBL

    ISSN:0074-1809

  37. CO(J=3-2) Observations of MS 1512-cB58 at z=2.72

    Nakanishi Kouichiro, Ohta Kouji, Takeuchi Tsutomu T., AKIYAMA Masayuki, YAMADA Toru, SHIOYA Yasuhiro

    PASJ : publications of the Astronomical Society of Japan 49 (5) 535-538 1997年10月25日

    出版者・発行元:Astronomical Society of Japan

    ISSN:0004-6264

  38. ASCA Large Sky Survey X線源の光学同定観測

    秋山正幸, 太田耕司, 山田亨, 上田佳宏, 高橋忠幸, 坂野正明, 鶴剛

    日本天文学会年会講演予稿集 1996 154 1996年

    ISSN:1347-0639

  39. ASCA LSSで見つかったHardなX線源の光学同定

    秋山正幸, 太田耕司, 山田亨, 上田佳宏, 高橋忠幸, 坂野正明, 鶴剛

    日本天文学会年会講演予稿集 1996 148 1996年

    ISSN:1347-0639

︎全件表示 ︎最初の5件までを表示

講演・口頭発表等 3

  1. Tomographic Wavefront Estimation for Wide-Field Adaptive Optics Sytems 国際会議

    International Symposium on Optical Memory 2016 2016年10月16日

  2. Toward Complete Understanding of Accretion History in the Universe and Its Relation to the Galaxy Formation 国際会議

    Joint Subaru/Gemini Science Conference 2009年5月18日

  3. Performance of Echidna fiber positioner for FMOS on Subaru 国際会議

    Scott Smedley, Peter Gillingham

    SPIE Astronomical Telescopes and Instrumentation 2008 2008年6月23日

共同研究・競争的資金等の研究課題 11

  1. 銀河中心の超大質量ブラックホールの宇宙論的進化の解明 競争的資金

    制度名:Basic Science Research Program

    1999年4月 ~ 継続中

  2. 銀河の形成と進化の観測的研究 競争的資金

    制度名:Cooperative Research

    1995年4月 ~ 継続中

  3. すばる望遠鏡での大気揺らぎ高度分布の統計的測定とその振る舞いの解明

    秋山 正幸

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research

    研究種目:Grant-in-Aid for Transformative Research Areas (A)

    研究機関:Tohoku University

    2021年9月10日 ~ 2023年3月31日

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    複数のレーザーガイド星での大気揺らぎ測定とトモグラフィー推定法を組み合わせたレーザートモグラフィー補償光学は高精度の補償光学を実現する上で必須の手法である。大気揺らぎのトモグラフィー推定の精度は、事前情報である大気揺らぎ高度分布が鍵を握り、リアルタイムで大気揺らぎ高度分布の情報を取得することが課題となっている。 我々は2台のシャックハルトマン波面センサーを搭載した小型望遠鏡を、すばる望遠鏡のドーム内に設置し、大気揺らぎ高度分布の測定を行うため、必要となる測定系のパラメータの決定と設計を行った。特に地表付近の大気揺らぎをSLODARの手法で高い高度分解能で測定し、上空の大気揺らぎをSH-MASSを用いたシンチレーションの空間スケールで測定するために、瞳上で2cmのサンプリングとすることを決めて光学設計を固めた。光学設計の仕様に基づき、必要な望遠鏡、架台、光学系、光学機械系の購入と組み上げを進めた。 並行して、すばる望遠鏡にプロトタイプとなるシャックハルトマン波面センサーの測定系を搭載した測定を行うため、光学系の組み上げと、望遠鏡焦点への取り付けに向けた機械系の設計を行った。次年度前半には試験の測定を行い、大気揺らぎ高度分布の測定の精度の評価や問題点の洗い出しを行う予定である。 レーザートモグラフィー補償光学の波面測定ユニットは東北大学での組み上げおよび光学調整を完了した。今後はデータの取得とリアルタイムの波面推定計算のコードを組み込み、実時間の波面測定のシステムを完成させる。

  4. すばる望遠鏡トモグラフィー補償光学で明かす銀河骨格の確立過程

    秋山 正幸, 岩田 生, 小山 佑世, 高遠 徳尚, 有本 信雄, 美濃和 陽典

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (S)

    研究種目:Grant-in-Aid for Scientific Research (S)

    研究機関:Tohoku University

    2017年5月31日 ~ 2022年3月31日

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    2017年度に引き続き1台のシャックハルトマン波面センサーの光学調整を行った。アライメントテレスコープを用いた光学調整の後、レーザーガイド星の高さ変化を模擬する光学系と組み合わせ、焦点成分の追随によって瞳径の変化が見られないように制御系の実装を行った。波面測定に必要となる画像処理ソフトウェアの実装を行った。また波面センサーの製作結果に基づいて、トモグラフィー波面測定ユニットの焦点調整系の製作を行った。 またレーザーガイド星システムについては、国立天文台ハワイ観測所の美濃和を中心に昨年度から繰り越されたレーザー光源の現地調整作業を進め、実験室において性能が出ていることを確認した。レーザー光源を既存のレーザー送信望遠鏡に導入し、複数のレーザーガイド星を実現するための光学系の設計を完了し、製作に必要な物品の購入を行った。また可変形鏡の更新に必要となる駆動回路系の購入を行った。 準備研究としてハッブル宇宙望遠鏡の高い空間分解能撮像データを用いて赤方偏移1から現在に渡って、円盤銀河内部の星の分布と星形成率の分布の宇宙論的進化について研究を進めた。赤方偏移1から現在の宇宙に渡って観測された円盤銀河内部の星の分布の進化はその期間の星形成率の空間分布を積算することで説明され、形成された星が動径方向に移動するような現象は特に必要ではないことが示唆された。この結果について論文として出版した。また、既存の補償光学を用いた高い空間分解能での活動銀河中心核の観測結果についても論文を出版した。

  5. すばる望遠鏡による超広視野の多天体補償光学の実証

    秋山 正幸, 大屋 真

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    研究種目:Grant-in-Aid for Scientific Research (B)

    研究機関:Tohoku University

    2014年4月1日 ~ 2017年3月31日

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    広視野補償光学を実現するトモグラフィー波面推定の新しいアルゴリズムとして、複タイムステップ・トモグラフィック波面推定の手法を、すばる望遠鏡の持込み装置である多天体補償光学実証機 RAVEN を用いて実証した。RAVEN の波面センサーの解析により、各高さの大気揺らぎが風向きにより時間と共に移動していること、相関のピークの強度は100ms程度までは強く、この時間間隔では大気揺らぎの各層が「凍結して移動している」と見なせることがわかり、複タイムステップ・トモグラフィック波面推定の有効性が実証された。

  6. 次世代多天体補償光学系に向けたトモグラフィック波面推定の高速化、高精度化

    秋山 正幸

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)

    研究種目:Grant-in-Aid for Young Scientists (B)

    研究機関:Tohoku University

    2011年 ~ 2012年

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    次世代超大型地上望遠鏡での広視野多天体の同時補償光学観測を可能にする大気揺らぎの高さ構造のトモグラフィーを用いた推定について、高精度化と高速度化を目指した検討を行った。広視野における高精度化については、風による大気移動によって時間変動が起こることを考慮した新しいアルゴリズムで推定精度を大きく向上できることがわかった。高速度化についてはグラフィックボードを用いた並列計算GPGPUを導入し、共役勾配法の収束を良くするために推定の初期値の改良を行う、並列計算の並列数を上げる、により達成可能である。

  7. 赤い銀河の星と塵の記憶から探る宇宙の星形成史

    花見 仁史, 秋山 正幸, 中西 康一郎, 松浦 周二

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    研究種目:Grant-in-Aid for Scientific Research (B)

    研究機関:Iwate University

    2009年 ~ 2012年

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    すばる望遠鏡で検出した約10 万個の銀河について、赤方偏移、星質量、吸収量、星形成率を出し、多波長データベースを作成した。また、この一部の約1000 個の赤外線銀河について、それらの活動起源を星形成、活動的中心核、星形成+活動的中心核に分類し、星形成よりも巨大ブラックホールが潜む活動的中心核が卓越する後者2つの活動が赤方偏移1前後で急激に進化していること、また、その質量膠着率と成長率を明らかにした.

  8. すばる望遠鏡近赤外線多天体分光器で探る巨大ブラックホールの成長史

    秋山 正幸

    提供機関:Japan Society for the Promotion of Science

    制度名:Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)

    研究種目:Grant-in-Aid for Young Scientists (B)

    2006年 ~ 2008年

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    この研究では近傍宇宙の銀河の中心に見つかっている巨大ブラックホールの宇宙論的な成長の歴史を統計的に明らかにするため、X線での探査で見つかった活動銀河中心核の可視赤外線分光観測による追求観測を行った。特に可視光では暗く、赤外線で明るいX線源の正体(赤方偏移(=存在する距離)や物理的性質)を、明らかにするために「すばる」望遠鏡の近赤外線多天体分光器を用いて、多数の天体の赤外線分光観測を行った。結果、これらの天体は80億年から100億年前の隠された活動銀河中心核であることがわかった。今回の結果はこの時代の宇宙の隠された活動銀河核でのブラックホールの降着成長が巨大ブラックホールの成長史の中で重要であることを示唆している。

  9. すばるFMOSによるバリオン振動探査計画の検討

    戸谷 友則, 太田 耕司, 岩室 史英, 秋山 正幸, 田村 直之

    2007年 ~ 2007年

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    現在の最新宇宙論における重要問題はいくつかあるが、その最大のものは「宇宙のダークサイド(暗黒面)」という言葉で以下の三つにまとめることができる。すなわち、(1)宇宙を加速膨張させる「ダークエネルギー」、(2)宇宙の重力を支配する「ダークマター(暗黒物質)」、そして(3)宇宙の晴れ上がりから最初の天体形成と宇宙再電離をつなぐ「ダークエイジ(暗黒時代)」である。その中でも、ダークエネルギーは現代物理学の根源的な改訂につながる可能性すら秘めた、とくに重大な問題として認識されている。 すばる望遠鏡の新観測装置FMOSを用いたバリオン振動探査計画により、このダークエネルギーに迫る事ができると期待されている。本研究の目的は、このバリオン振動探査計画のサーベイデザインを検討し、FMOS完成の際にすみやかに観測提案書を作成する準備を進める事にある。 この目的のため、戸谷を中心に分光ターゲット銀河選定の手法や実現性を詳細にしらべた。「すばるディープフィールド」や、「すばるXMM-Newtonディープフィールド」と呼ばれる領域のすばる望遠鏡を中心とする膨大なデータをもとに、バリオン振動探査に使用できる銀河が十分に存在するかどうかを精査した。その結果、バリオン振動探査に十分な数の銀河があり、また、イメージングサーベイデータから測光的赤方偏移計算の手法により効率よく選択できる事も判明した。 また、メンバーがハワイに集まってミーティングを開催し、FMOS装置に対する理解を深めるとともに、今後の問題点を洗い出して計画の推進に役立てた。国際的な注目も高く、国際会議で進捗状況を報告した。

  10. 遠方宇宙での銀河中心巨大ブラックホールの成長過程

    秋山 正幸

    2004年 ~ 2006年

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    すばる望遠鏡の多天体分光観測装置FOCASを用いて、すばるXMM-ニュートン深探査領域において見つかったX線源の可視分光観測を行い、X線源の距離、正体の決定をした。遠方宇宙にある活動銀河中心核が新たに多数発見された。特に、遠方宇宙に数多くの隠された活動銀河中心核があることが見えてきた。過去の観測結果に基づくモデルなどとの比較はこれから行う。結果は来年度に論文化する予定である。 また、遠方宇宙での銀河の進化の様子を調べるために、すばる望遠鏡の補償光学(アダプティブオピティクス、AO)と赤外線カメラIRCSを用いて、遠方銀河の撮像探査観測を行った。このデータ解析は現在進行中である。 さらに、GOODS深探査領域の活動銀河中心核の母銀河について、ハッブル宇宙望遠鏡を用いて得られた撮像データを用い、母銀河の星質量、星形成率を求めた。特に近傍宇宙で見られる銀河中心ブラックホールと銀河の質量の関係が遠方宇宙においてどのように変化しているかに注目した。結果、遠方宇宙の活動銀河核では、同じブラックホール質量で比較すると、銀河の星質量が近傍宇宙の活動銀河核に比べて小さいことがわかった。このことは銀河中心のブラックホールが先に形成され、銀河の形成が後に続くことを示唆している。ただし、遠方宇宙の活動銀河核では近傍宇宙のものよりもエディントン比が大きい、という仮定でも解釈できる結果であり、銀河とブラックホールの進化を明確に議論するにはさらに観測が必要である。

  11. 「あすか」による広域深宇宙探査の光学同定及び活動的銀河の研究

    秋山 正幸

    1998年 ~ 1999年

︎全件表示 ︎最初の5件までを表示

担当経験のある科目(授業) 2

  1. 観測天文学

  2. 星間物理学 東北大学

社会貢献活動 4

  1. 天文学入門 NHKカルチャー

    2023年4月1日 ~ 継続中

  2. サイエンス講座「ハワイの山から宇宙を観れば」

    2023年3月5日 ~ 2023年3月5日

  3. さくらサイエンスプラン

    2016年8月 ~ 2017年3月

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    中国の大学の学部生対象に天文データ解析の実習講座を行う。

  4. 科学者の卵養成講座

    2009年8月1日 ~ 2012年3月

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    高校生向け夏休み実習講座を行った。

その他 7

  1. TMT-AGE:すばる望遠鏡でのトモグラフィー補償光学の実証

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    すばる望遠鏡に複数の波面センサーを取り付けてトモグラフィー補償光学の実証試験を行う。

  2. Evolution of SMBHs with HSC: First results from initial dataset

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    すばる望遠鏡 Hyper Suprime Cam の大規模データを用いた QSO 探査について国際研究会を開催する。

  3. TMT-AGE:TMT Analyzer for Galaxies in the Early universe

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    次世代30m望遠鏡において多天体補償光学を実現するために補償光学のシステムとしての検討を行う。補償光学の光学設計、機械設計、補償光学の計算機シミュレーションおよびすばる望遠鏡を用いた実証試験を行う。

  4. 超広域サーベイで明かす巨大ブラックホールと銀河の共進化:理論モデルと観測戦略

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    すばる望遠鏡で観測を開始する超広視野カメラを用いた観測により銀河と巨大ブラックホールの宇宙論的進化を明らかにする。

  5. TMT多天体補償光学系の実現に向けた実証試験

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    次世代30m地上望遠鏡用の多天体補償光学系の実現に向けて、実験室での実証試験を進めている。この共同開発研究では特に高速の波面センサーの開発のために、高速低ノイズ読みだしのCCDの評価実験を行った。

  6. 次世代30m望遠鏡多天体補償光学システム用の可変形鏡の試作および評価

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    次世代の補償光学系の実現に必要となる多素子、大ストロークのMEMS可変形鏡の開発を行った。

  7. すばる望遠鏡を用いた多天体補償光学系の実証

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    すばる望遠鏡を用いて多天体補償光学系を実証する。複数の波面センサーを用いて、複数の星からの光の波面を計測し、トモグラフィーの手法を用いて解析することで、大気揺らぎの情報を高さ方向に分解して推定する。推定結果を任意の方向に積分することで、任意の方向の天体について補償光学を適用する。

︎全件表示 ︎最初の5件までを表示