Details of the Researcher

PHOTO

Shigeo Kimura
Section
Frontier Research Institute for Interdisciplinary Sciences
Job title
Associate Professor
Degree

Research History 7

  • 2025/04 - Present
    Tohoku University　Frontier Research Institute for Interdisciplinary Sciences Creative Interdisciplinary Research Division

  • 2022/04 - Present
    Tohoku University　Frontier Research Institute for Interdisciplinary Sciences Creative Interdisciplinary Research Division　Assistant Professor

  • 2019/04 - 2022/03
    Tohoku University　Frontier Research Institute for Interdisciplinary Sciences　JSPS Research Fellow

  • 2018/04 - 2019/03
    Pennsylvania State University　Department of Physics　JSPS Overseas Research Fellow

  • 2016/09 - 2018/03
    Pennsylvania State University　Eberly College of Science　Postdoctoral Researcher

  • 2015/04 - 2016/08
    Tohoku University　Frontier Research Institute for Interdisciplinary Sciences　Postdoctoral Researcher

  • 2013/04 - 2015/03
    Osaka University　Graduate School of Science

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Education 1

  • Osaka University　Graduate School of Science　Department of Earth and Space Science

    2010/04 - 2015/03

Committee Memberships 1

  • 日本天文学会　男女共同参画委員会

    2025/06 - Present

Professional Memberships 3

  • 理論天文学宇宙物理学懇談会

  • 日本物理学会

  • 日本天文学会

Research Interests 6

  • ガンマ線

  • 粒子加速

  • 宇宙線

  • ニュートリノ天文学

  • ブラックホール

  • 宇宙物理学

Research Areas 2

  • Natural sciences / Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics /

  • Natural sciences / Astronomy /

Awards 3

  1. 科学技術分野の文部科学大臣表彰 若手科学者賞

    2024/04　ブラックホール降着流における高エネルギー現象の理論的研究

  2. ASJ Young Astronomer Award

    2023/03　Astronomical Society of Japan　Theoretical Study of Cosmic-ray Acceleration and High-energy Emission around Black Holes

  3. Young Scientist Award of the Physical Society of Japan

    2021/03　Physical Society of Japan　Theoretical Study of High Energy Phenomena in Black Hole Accretion Flows

Papers 83

  1. Little red dots as hidden neutrino sources Peer-reviewed

    Kuze, Riku, Ioka, Kunihito, Murase, Kohta, Kimura, Shigeo S., Inayoshi, Kohei

    Phys.Rev.D　113　(8)　083048-083048　2026/04/15

    DOI： 10.1103/vbfz-ncxd 　

  2. Neutrino and electromagnetic signatures from Superluminous Supernovae: a case study for SN 2017egm

    Mukhopadhyay, Mainak, Kimura, Shigeo S., Vurm, Indrek, Metzger, Brian D.

    2026/03

  3. IceCube's convex all-sky neutrino spectrum consistent with the magnetically powered corona scenario for active galactic nuclei

    Murase, Kohta, Kimura, Shigeo S., Mukhopadhyay, Mainak, Bhattacharya, Mukul

    2026/02

  4. Spectral Shapes of Pair Annihilation Line Emission in Magnetar Giant Flares Peer-reviewed

    Wada, Tomoki, Kimura, Shigeo S.

    Astrophys.J.Lett.　997　(1)　2026/01/14

    DOI： 10.3847/2041-8213/ae3289 　

  5. High energy neutrinos from pulsar-powered optical transients: LFBOTs as potential origin of the KM3NeT event KM3-230213A

    Mukhopadhyay, Mainak, Kimura, Shigeo S.

    2026/01

  6. Microquasar jet-cocoon systems as PeVatrons Peer-reviewed

    Zhang, B. Theodore, Kimura, Shigeo S., Murase, Kohta

    Phys.Rev.D　112　(12)　123015-123015　2025/12/05

    DOI： 10.1103/p6r1-qg5q 　

  7. The First Search for Optical Transient as a Counterpart of a Month-timescale IceCube Neutrino Multiplet Event Peer-reviewed

    Toshikage, Seiji, Kimura, Shigeo S., Shimizu, Nobuhiro, Tanaka, Masaomi, Yoshida, Shigeru, Iwakiri, Wataru B., Morokuma, Tomoki

    Astrophys.J.　993　(1)　23-23　2025/10/23

    DOI： 10.3847/1538-4357/adfedf 　

  8. Concept of high-z gamma-ray bursts unraveling the dark ages and extreme space-time mission—HiZ-GUNDAM Peer-reviewed

    Daisuke Yonetoku, Akihiro Doi, Tatehiro Mihara, Hideo Matsuhara, Takanori Sakamoto, Kohji Tsumura, Kunihito Ioka, Makoto Arimoto, Yoshiyuki Ando, Teruaki Enoto, Kenjiro Fujimoto, Hatsune Goto, Junko Hiraga, Nobuyuki Kawai, Ryuji Kondo, Shunsuke Kurosawa, Yoshitomo Maeda, Ikuyuki Mitsuishi, Toshio Murakami, Issin Nagataka, Yujin Nakagawa, Hiroshi Nakajima, Naoki Ogino, Masataka Sato, Tomoya Sato, Tatsuya Sawano, Motoko Serino, Hsien-Chieh Shen, Satoshi Sugita, Mutsumi Sugizaki, Shuta Takahashi, Toru Tamagawa, Keisuke Tamura, Takaaki Tanaka, Toru Tanimori, Makoto S. Tashiro, Hiroshi Tomida, Hiroyuki Uchida, Shutaro Ueda, Kazutaka Yamaoka, Makoto Yamauchi, Yoichi Yatsu, Atsumasa Yoshida, Hiroshi Akitaya, Akihiko Fukui, Haruki Fukui, Ryo Hashimoto, Tomoya Hori, Yoshifusa Ita, Rinon Kageyama, Koji Kawabata, Shuji Matsuura, Akihiro Miyasaka, Kentaro Motohara, Norio Narita, Hirofumi Noda, Hirofumi Okita, Kei Sano, Keisuke Shinozaki, Sou Tajima, Yuji Urata, Takehiko Wada, Hayato Yamashita, Kenshi Yanagisawa, Michitoshi Yoshida, Shuichi Gunji, Takumi Togashi, Ryuji Sato, Keito Watanabe, Haruaki Niinuma, Nobutaka Bando, Ichiro Jikuya, Kenji Minesugi, Yasuyuki Miyazaki, Yusuke Kono, Naoki Takase, Shinichi Nakatsubo, Tooru Kaga, Katsuaki Asano, Kohei Inayoshi, Susumu Inoue, Hirotaka Ito, Hideyuki Izumiura, Norita Kawanaka, Tomoya Kinugawa, Shota Kisaka, Kenta Kiuchi, Koutarou Kyutoku, Jin Matsumoto, Akira Mizuta, Kohta Murase, Hiroki Nagakura, Shigehiro Nagataki, Yoshikazu Nakada, Takashi Nakamura, Yuu Niino, Yudai Suwa, Keitaro Takahashi, Takahiro Tanaka, Kenji Toma, Tomonori Totani, Ryo Yamazaki, Jun’ichi Yokoyama, Yuichi Harikane, Masaomi Tanaka, Shigeo S. Kimura, Mariko Kimura, Hiroya Umeda

    Journal of Astronomical Telescopes, Instruments, and Systems　11　(04)　2025/10/18

    Publisher: SPIE-Intl Soc Optical Eng

    DOI： 10.1117/1.jatis.11.4.044002 　

    ISSN： 2329-4124

  9. Electromagnetic Signatures from Pulsar Remnants of Binary Neutron Star Mergers: Prospects for Unique Identification Using Multiwavelength Signatures Peer-reviewed

    Mukhopadhyay, Mainak, Kimura, Shigeo S.

    Astrophys.J.Lett.　989　(2)　2025/08/14

    DOI： 10.3847/2041-8213/adf285 　

  10. Formation and Early Evolution of Protoplanetary Disks under Nonuniform Cosmic-Ray Ionization Peer-reviewed

    Nishio, Erika, Tomida, Kengo, Kudoh, Yuki, Kimura, Shigeo S.

    Astrophys.J.　988　(1)　56-56　2025/07/14

    DOI： 10.3847/1538-4357/addbe2 　

  11. High-energy Neutrino Signatures from Pulsar Remnants of Binary Neutron-star Mergers: Coincident Detection Prospects with Gravitational Waves Peer-reviewed

    Mainak Mukhopadhyay, Shigeo S. Kimura, Brian D. Metzger

    The Astrophysical Journal　987　(2)　218-218　2025/07/09

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/adc913 　

    ISSN： 0004-637X

    eISSN： 1538-4357

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    Abstract Binary neutron-star (BNS) mergers are accompanied by multimessenger emissions, including gravitational wave (GW), neutrino, and electromagnetic signals. Some fraction of BNS mergers may result in a rapidly spinning magnetar as a remnant, which can enhance both the EM and neutrino emissions. In this study, we model the neutrino emissions from such systems and discuss the prospects for detecting the neutrinos coincident with GW signatures. We consider a scenario where a magnetar remnant drives a pulsar wind using its spin energy. The wind interacts with the surrounding kilonova ejecta, forming a nebula filled with nonthermal photons. Ions and nuclei extracted from the magnetar’s surface can be accelerated in the polar-cap and the termination-shock regions. We investigate the neutrino fluences resulting from photomeson interactions, where accelerated CR protons interact with the photons in the nebula. Our findings indicate that the peak neutrino fluence is ∼10−2 GeV cm−2 for a source at 40 Mpc, which is reached approximately post-merger. Finally, we examine the potential for GW-triggered stacking searches with IceCube-Gen2 using next-generation GW detectors such as the Cosmic Explorer (CE) and the Einstein Telescope (ET). We conclude that, assuming an optimistic neutrino emission model, a combination of CE+ET would offer a high probability of neutrino detection from these sources within an operational timescale of ∼20 yr. In case of nondetection, 2σ level constraints on model parameters can be established within similar joint operation timescales.

  12. J1406+0102: A Dust-obscured Galaxy Hiding a Super-Eddington Accretion System with Bright Radio Emission Peer-reviewed

    Hikaru Fukuchi, Kohei Ichikawa, Masayuki Akiyama, Shigeo S. Kimura, Yoshiki Toba, Kohei Inayoshi, Akatoki Noboriguchi, Toshihiro Kawaguchi, Xiaoyang Chen, Itsna K. Fitriana

    The Astrophysical Journal　987　(1)　66-66　2025/06/27

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/add478 　

    ISSN： 0004-637X

    eISSN： 1538-4357

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    Abstract Recent high-z quasar observations strongly indicate that super-Eddington accretion is a crucial phase to describe the presence of supermassive black holes (SMBHs) with M BH ≳ 109 M ⊙ at z ≳ 7. Motivated by theoretical predictions that the super-Eddington phase efficiently produces outflows and bright jets in radio bands, we identify a super-Eddington radio-loud dust-obscured galaxy (DOG) J1406+0102 at z = 0.2367. This source is discovered by cross-matching the infrared-bright DOGs of A. Noboriguchi et al. with the Very Large Array/Far-Infrared and Submillimetre Telescope 1.4 GHz radio survey data and the Sloan Digital Sky Survey optical spectral catalog. J1406+0102 shows broad components in the Balmer lines, and by assuming that those lines are from the broad-line region, they give black hole (BH) mass estimations of . Combined with an active galactic nucleus (AGN) luminosity of estimated from the intrinsic [O iii] luminosity, this implies a super-Eddington accretion rate of λ Edd ≃ 3. We show that (1) J1406+0102 shows strong AGN feedback, with the [O i ii] outflow velocity exceeding the escape velocity of the host galaxy halo and a kinetic efficiency of ≈8%, sufficient to quench the host galaxy; (2) its expected growth trajectory places it on an overmassive BH track; and (3) if representative of radio-loud DOGs, such sources can contribute significantly to the high-energy (≳100 TeV) cosmic neutrino background.

  13. Detection Prospects of Electromagnetic Signatures from OGLE-2011-BLG-0462 Peer-reviewed

    Shigeo S. Kimura, Elena Murchikova, Kailash C. Sahu

    Astrophys.J.　986　(2)　135-135　2025/06/12

    DOI： 10.3847/1538-4357/add52c 　

  14. Weakness of X-rays and variability in high-redshift active galactic nuclei with super-Eddington accretion Peer-reviewed

    Kohei Inayoshi, Shigeo S Kimura, Hirofumi Noda

    Publications of the Astronomical Society of Japan　2025/06/10

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/pasj/psaf050 　

    ISSN： 0004-6264

    eISSN： 2053-051X

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    Abstract JWST observations have enabled the exploration of active galactic nuclei (AGNs) with broad-line emission in the early Universe. Despite the clear radiative and morphological signatures of AGNs in rest-frame optical bands, complementary evidence of AGN activity—such as X-ray emission and ultraviolet/optical variability—remains rarely detected. The weakness of X-rays and variability in these broad-line emitters challenges the conventional AGN paradigm, indicating that the accretion processes or environments around the central black holes (BHs) differ from those of their low-redshift counterparts. In this work, we study the radiation spectra of super-Eddington accretion disks enveloped by high-density coronae. Radiation-driven outflows from the disk transport mass to the poles, resulting in moderately optically thick, warm coronae formed through effective inverse Comptonization. This mechanism leads to softer X-ray spectra and larger bolometric correction factors for X-rays compared with typical AGNs, while being consistent with those of JWST AGNs and low-redshift super-Eddington accreting AGNs. In this scenario, ultraviolet/optical variability is suppressed due to photon trapping within super-Eddington disks, while X-ray emissions remain weak yet exhibit significant relative variability. These characteristics are particularly evident in high-redshift AGNs powered by lower-mass BHs with $\lesssim 10^{7-8}$ M$_\odot$, which undergo rapid mass accretion following overmassive evolutionary tracks relative to the BH-to-stellar mass correlation in the local Universe.

  15. EP240414a: A Gamma-Ray Burst Jet Weakened by an Extended Circumstellar Material Peer-reviewed

    Hamid Hamidani, Yuri Sato, Kazumi Kashiyama, Masaomi Tanaka, Kunihito Ioka, Shigeo S. Kimura

    Astrophys.J.Lett.　986　(1)　2025/06/04

    DOI： 10.3847/2041-8213/add99d 　

  16. Galactic Isolated Stellar-mass Black Holes with the Magnetospheric Spark Gap as Possible GeV–TeV Gamma-Ray Unidentified Sources Peer-reviewed

    Koki Kin, Riku Kuze, Shigeo S. Kimura

    Astrophys.J.　985　(2)　251-251　2025/05/29

    DOI： 10.3847/1538-4357/adcb3d 　

  17. Multimessenger Emission by Magnetically Arrested Disks and Relativistic Jets of Black Hole X-Ray Binaries Peer-reviewed

    Riku Kuze, Shigeo S. Kimura, Ke Fang

    Astrophys.J.　985　(1)　139-139　2025/05/20

    DOI： 10.3847/1538-4357/adcc1b 　

  18. High-energy Gamma-Ray and Neutrino Emissions from Interacting Supernovae Based on Radiation Hydrodynamic Simulations: A Case of SN 2023ixf Peer-reviewed

    Shigeo S. Kimura, Takashi Moriya

    Astrophys.J.　984　(2)　103-103　2025/05/02

    DOI： 10.3847/1538-4357/adc716 　

  19. Isolated Black Holes as Potential PeVatrons and Ultrahigh-energy Gamma-Ray Sources Peer-reviewed

    Shigeo S. Kimura, Kengo Tomida, Masato I. N. Kobayashi, Koki Kin, Bing Zhang

    The Astrophysical Journal Letters　981　(2)　L36-L36　2025/03/10

    Publisher: American Astronomical Society

    DOI： 10.3847/2041-8213/adb841 　

    ISSN： 2041-8205

    eISSN： 2041-8213

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    Abstract The origin of PeV cosmic rays (CRs) is a long-standing mystery, and ultrahigh-energy gamma-ray observations would play a crucial role in identifying it. Recently, LHAASO reported the discovery of “dark” gamma-ray sources that were detected above 100 TeV without any GeV–TeV gamma-ray counterparts. The origins of these dark gamma-ray sources are unknown. We propose isolated black holes (IBHs) wandering in molecular clouds as the origins of PeV CRs and LHAASO dark sources. An IBH accretes surrounding dense gas, which forms a magnetically arrested disk (MAD) around the IBH. Magnetic reconnection in the MAD can accelerate CR protons up to PeV energies. CR protons of GeV–TeV energies fall to the IBH, whereas CR protons at sub-PeV energies can escape from the MAD, providing PeV CRs into the interstellar medium. The sub-PeV CR protons interact with the surrounding molecular clouds, producing TeV–PeV gamma rays without emitting GeV–TeV gamma rays. This scenario can explain the dark sources detected by LHAASO. Taking into account the IBH and molecular cloud distributions in our Galaxy, we demonstrate that IBHs can provide a significant contribution to the PeV CRs observed on Earth. Future gamma-ray detectors in the southern sky and neutrino detectors would provide a concrete test to our scenario.

  20. Detection of Extended X-Ray Emission around the PeVatron Microquasar V4641 Sgr with XRISM Peer-reviewed

    Hiromasa Suzuki, Naomi Tsuji, Yoshiaki Kanemaru, Megumi Shidatsu, Laura Olivera-Nieto, Samar Safi-Harb, Shigeo S. Kimura, Eduardo de la Fuente, Sabrina Casanova, Kaya Mori, Xiaojie Wang, 孔毅 胡, Dai Tateishi, Hideki Uchiyama, Takaaki Tanaka, Hiroyuki Uchida, Shun Inoue, Dezhi Huang, Marianne LEMOINE-GOUMARD, Daiki Miura, Shoji Ogawa, Shogo B. Kobayashi, chris done, Maxime Parra, Maria Diaz Trigo, Teo Muñoz Darias, Montserrat Armas Padilla, Ryota Tomaru, Yoshihiro Ueda

    Astrophys.J.Lett.　978　(2)　2025/01/03

    DOI： 10.3847/2041-8213/ad9d11 　

  21. Multiwavelength Emission from Jets and Magnetically Arrested Disks in Nearby Radio Galaxies: Application to M87 Peer-reviewed

    Riku Kuze, Shigeo S. Kimura, Kenji Toma

    Astrophys.J.　977　(1)　22-22　2024/11/29

    DOI： 10.3847/1538-4357/ad88f4 　

  22. High-energy Neutrinos from Late-time Jets of Gamma-Ray Bursts Seeded with Cocoon Photons Peer-reviewed

    Riki Matsui, Shigeo S. Kimura, Hamid Hamidani

    Astrophys.J.　974　(2)　185-185　2024/10/11

    DOI： 10.3847/1538-4357/ad6f09 　

  23. Ultrahigh-energy neutrino searches using next-generation gravitational wave detectors at radio neutrino detectors: GRAND, IceCube-Gen2 Radio, and RNO-G Peer-reviewed

    Mainak Mukhopadhyay, Kumiko Kotera, Stephanie Wissel, Kohta Murase, Shigeo S. Kimura

    Phys.Rev.D　110　(6)　063004-063004　2024/09/03

    DOI： 10.1103/PhysRevD.110.063004 　

  24. Inertial range of magnetorotational turbulence Peer-reviewed

    Yohei Kawazura, Shigeo S. Kimura

    Sci.Adv.　10　(35)　2024/08/30

    DOI： 10.1126/sciadv.adp4965 　

  25. GRB 211211A: The Case for an Engine-powered over r-process-powered Blue Kilonova Peer-reviewed

    Hamid Hamidani, Masaomi Tanaka, Shigeo S. Kimura, Gavin P. Lamb, Kyohei Kawaguchi

    The Astrophysical Journal Letters　971　(2)　L30-L30　2024/08/01

    Publisher: American Astronomical Society

    DOI： 10.3847/2041-8213/ad6864 　

    ISSN： 2041-8205

    eISSN： 2041-8213

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    Abstract The recent gamma-ray burst (GRB) GRB 211211A provides the earliest (∼5 hr) data of a kilonova (KN) event, displaying bright (∼1042 erg s−1) and blue early emission. Previously, this KN was explained using simplistic multicomponent fitting methods. Here, in order to understand the physical origin of the KN emission in GRB 211211A, we employ an analytic multizone model for r-process-powered KNe. We find that r-process-powered KN models alone cannot explain the fast temporal evolution and the spectral energy distribution (SED) of the observed emission. Specifically, (i) r-process models require high ejecta mass to match early luminosity, which overpredicts late-time emission, while (ii) red KN models that reproduce late emission underpredict early luminosity. We propose an alternative scenario involving early contributions from the GRB central engine via a late low-power jet, consistent with plateau emission in short GRBs and GeV emission detected by Fermi-LAT at ∼104 s after GRB 211211A. Such late central engine activity, with an energy budget of ∼a few percent of that of the prompt jet, combined with a single red KN ejecta component, can naturally explain the light curve and SED of the observed emission, with the late-jet–ejecta interaction reproducing the early blue emission and r-process heating reproducing the late red emission. This supports claims that late low-power engine activity after prompt emission may be common. We encourage early follow-up observations of future nearby GRBs and compact binary merger events to reveal more about the central engine of GRBs and r-process events.

  26. Shock Cooling and Breakout Emission for Optical Flares Associated with Gravitational-wave Events Peer-reviewed

    Hiromichi Tagawa, Shigeo S. Kimura, Zoltan Haiman, Rosalba Perna, Bartos, Imre

    Astrophys.J.　966　(1)　21-21　2024/04/23

    DOI： 10.3847/1538-4357/ad2e0b 　

  27. One-dimensional General Relativistic Particle-in-cell Simulations of Stellar-mass Black Hole Magnetospheres: A Semianalytic Model of Gamma-Rays from Gaps Peer-reviewed

    Koki Kin, Shota Kisaka, Kenji Toma, Shigeo S. Kimura, Amir Levinson

    Astrophys.J.　964　(1)　78-78　2024/03/18

    DOI： 10.3847/1538-4357/ad20cd 　

  28. Late Engine Activity in Neutron Star Mergers and Its Cocoon: An Alternative Scenario for the Blue Kilonova Peer-reviewed

    Hamid Hamidani, Shigeo S. Kimura, Masaomi Tanaka, Kunihito Ioka

    Astrophys.J.　963　(2)　137-137　2024/03/07

    DOI： 10.3847/1538-4357/ad20d0 　

  29. Gravitational wave triggered searches for high-energy neutrinos from binary neutron star mergers: Prospects for next generation detectors Peer-reviewed

    Mainak Mukhopadhyay, Shigeo S. Kimura, Kohta Murase

    Phys.Rev.D　109　(4)　043053-043053　2024/02/15

    DOI： 10.1103/PhysRevD.109.043053 　

  30. Sub-GeV Gamma Rays from Nearby Seyfert Galaxies and Implications for Coronal Neutrino Emission Peer-reviewed

    Kohta Murase, Christopher Karwin, Shigeo S. Kimura, Marco Ajello, Sara Buson

    Astrophys.J.Lett.　961　(2)　2024/01/31

    DOI： 10.3847/2041-8213/ad19c5 　

  31. A New Insight into Electron Acceleration Properties from Theoretical Modeling of Double-peaked Radio Light Curves in Core-collapse Supernovae Peer-reviewed

    Tomoki Matsuoka, Shigeo S. Kimura, Keiichi Maeda, Masaomi Tanaka

    Astrophys.J.　960　(1)　70-70　2024/01

    DOI： 10.3847/1538-4357/ad096c 　

  32. High-energy Electromagnetic, Neutrino, and Cosmic-Ray Emission by Stellar-mass Black Holes in Disks of Active Galactic Nuclei Peer-reviewed

    Hiromichi Tagawa, Shigeo S. Kimura, Zoltan Haiman

    Astrophys.J.　955　(1)　23-23　2023/09/12

    DOI： 10.3847/1538-4357/ace71d 　

  33. High-energy Neutrino Emission Associated with Gravitational-wave Signals: Effects of Cocoon Photons and Constraints on Late-time Emission Peer-reviewed

    Riki Matsui, Shigeo S. Kimura, Kenji Toma, Kohta Murase

    Astrophys.J.　950　(2)　190-190　2023/06/26

    DOI： 10.3847/1538-4357/acd004 　

  34. Observable Signature of Merging Stellar-mass Black Holes in Active Galactic Nuclei Peer-reviewed

    Hiromichi Tagawa, Shigeo S. Kimura, Zoltan Haiman, Rosalba Perna, Bartos, Imre

    Astrophys.J.　950　(1)　13-13　2023/06/06

    DOI： 10.3847/1538-4357/acc4bb 　

  35. Observable Signatures of Stellar-mass Black Holes in Active Galactic Nuclei Peer-reviewed

    Hiromichi Tagawa, Shigeo S. Kimura, Zoltan Haiman, Rosalba Perna, Imre Bartos

    Astrophys.J.Lett.　946　(1)　2023/03/21

    DOI： 10.3847/2041-8213/acc103 　

  36. Synchrotron Polarization of Gamma-Ray Burst Afterglow Shocks with Hydrodynamic-scale Turbulent Magnetic Field Peer-reviewed

    Asuka Kuwata, Kenji Toma, Shigeo S. Kimura, Sara TOMITA, Jiro Shimoda

    Astrophys.J.　943　(2)　118-118　2023/02/01

    DOI： 10.3847/1538-4357/acac88 　

  37. Modeling Hadronic Gamma-Ray Emissions from Solar Flares and Prospects for Detecting Nonthermal Signatures from Protostars Peer-reviewed

    Shigeo S. Kimura, Shinsuke Takasao, Kengo Tomida

    The Astrophysical Journal　944　(2)　192-192　2023/02/01

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/acb649 　

    ISSN： 0004-637X

    eISSN： 1538-4357

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    Abstract We investigate gamma-ray emission in the impulsive phase of solar flares and the detectability of nonthermal signatures from protostellar flares. Energetic solar flares emit high-energy gamma rays of GeV energies, but their production mechanism and emission site are still unknown. Young stellar objects, including protostars, also exhibit luminous X-ray flares, but the triggering mechanism of the flaring activity is still unclear owing to the strong obscuration. Nonthermal signatures in millimeter/submillimeter and gamma-ray bands are useful to probe protostellar flares owing to their strong penetration power. We develop a nonthermal emission model of the impulsive phase of solar flares, where cosmic-ray protons accelerated at the termination shock produce high-energy gamma rays via hadronuclear interaction with the evaporation plasma. This model can reproduce gamma-ray data in the impulsive phase of a solar flare. We apply our model to protostellar flares and show that the Cherenkov Telescope Array will be able to detect gamma rays of TeV energies if particle acceleration in protostellar flares is efficient. Nonthermal electrons accelerated together with protons can emit strong millimeter and submillimeter signals via synchrotron radiation, whose power is consistent with the energetic millimeter/submillimeter transients observed from young stars. Future gamma-ray and millimeter/submillimeter observations from protostars, coordinated with a hard X-ray observation, will unravel the nonthermal particle production and triggering mechanism of protostellar flares.

  38. Neutrinos from the Brightest Gamma-Ray Burst?

    Kohta Murase, Mainak Mukhopadhyay, Ali Kheirandish, Shigeo S. Kimura, Ke Fang

    Astrophys.J.Lett.　941　(1)　2022/12/08

    DOI： 10.3847/2041-8213/aca3ae 　

  39. Magnetic Reconnection in Black Hole Magnetospheres: Lepton Loading into Jets, Superluminal Radio Blobs, and Multiwavelength Flares Peer-reviewed

    Shigeo S. Kimura, Kenji Toma, Hirofumi Noda, Kazuhiro Hada

    The Astrophysical Journal Letters　937　(2)　L34-L34　2022/10/01

    Publisher: American Astronomical Society

    DOI： 10.3847/2041-8213/ac8d5a 　

    ISSN： 2041-8205

    eISSN： 2041-8213

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    Abstract Supermassive black holes in active galactic nuclei launch relativistic jets, as indicated by observed superluminal radio blobs. The energy source of these jets is widely discussed in the theoretical framework of the Blandford–Znajek process, the electromagnetic energy extraction from rotating black holes (BHs), while the formation mechanism of the radio blobs in the electromagnetically dominated jets has been a long-standing problem. Recent high-resolution magnetohydrodynamic simulations of magnetically arrested disks exhibited magnetic reconnection in a transient magnetically dominated part of the equatorial disk near the BH horizon, which led to a promising scenario of efficient MeV gamma-ray production and subsequent electron–positron pair loading into the BH magnetosphere. We develop this scenario to build a theoretical framework on energetics, timescales, and particle number density of the superluminal radio blobs and discuss observable signatures in other wave bands. We analytically show that the nonthermal electrons emit broadband photons from optical to multi-MeV bands. The electron–positron pairs produced in the magnetosphere are optically thick for synchrotron self-absorption, so that the injected energy is stored in the plasma. The stored energy is enough to power the superluminal radio blobs observed in M87. This scenario predicts rather dim radio blobs around Sgr A*, which are consistent with no clear detection by current facilities. In addition, this scenario inevitably produces strong X-ray flares in a short timescale, which will be detectable by future X-ray satellites.

  40. Cosmic-Ray Ionization Rate in Protoplanetary Disks with Sheared Magnetic Fields Peer-reviewed

    Yuri I. Fujii, Shigeo S. Kimura

    Astrophys.J.Lett.　937　(2)　L37-L37　2022/09/30

    Publisher: American Astronomical Society

    DOI： 10.3847/2041-8213/ac86c2 　

    ISSN： 2041-8205

    eISSN： 2041-8213

    More details Close

    Abstract We investigate the effects of magnetic-field configurations on the ionization rate by cosmic rays in protoplanetary disks. First, we consider cosmic-ray propagation from the interstellar medium (ISM) to the protoplanetary disks and showed that the cosmic-ray density around the disk should be 2 times lower than the ISM value. Then, we compute the attenuation of cosmic rays in protoplanetary disks. The magnetic fields in the disk are stretched to the azimuthal directions, and cosmic rays need to detour while propagating to the midplane. Our results show that the detouring effectively enhances the column density by about two orders of magnitude. We employ a typical ionization rate by cosmic rays in diffuse ISM, which is considered too high to be consistent with observations of protoplanetary disks, and find that the cosmic rays are significantly shielded at the midplane. In the case of the disk around IM Lup, the midplane ionization rate is very low for r ≲ 100 au, while the value is as large as a diffuse ISM in the outer radii. Our results are consistent with the recent Atacama Large Millimeter/submillimeter Array observation that indicates the radial gradient in the cosmic-ray ionization rate. The high ionization rate in the outer radii of disks may activate the magnetorotational instability that was thought to be suppressed due to ambipolar diffusion. These results will have a strong influence on the dynamical and chemical evolutions of protoplanetary disks.

  41. Interaction of a Relativistic Magnetized Collisionless Shock with a Dense Clump Peer-reviewed

    Sara TOMITA, Yutaka Ohira, Shigeo S. Kimura, Kengo Tomida, Kenji Toma

    Astrophys.J.Lett.　936　(1)　2022/08/29

    DOI： 10.3847/2041-8213/ac88be 　

  42. High-energy Gamma Rays from Magnetically Arrested Disks in Nearby Radio Galaxies Peer-reviewed

    Riku Kuze, Shigeo S. Kimura, Kenji Toma

    Astrophys.J.　935　(2)　159-159　2022/08/23

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/ac7ec1 　

    ISSN： 0004-637X

    eISSN： 1538-4357

    More details Close

    Abstract The origins of the GeV gamma rays from nearby radio galaxies are unknown. Hadronic emission from magnetically arrested disks (MADs) around central black holes is proposed as a possible scenario. Particles are accelerated in a MAD by magnetic reconnection and stochastic turbulence acceleration. We pick out the 15 brightest radio galaxies in the GeV band from The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope, Data Release 2 and apply the MAD model. We find that we can explain the data in the GeV bands by the MAD model if the accretion rate is lower than 0.1% of the Eddington rate. For a higher accretion rate, GeV gamma rays are absorbed by two-photon interaction due to copious low-energy photons. If we assume another proposed prescription of the electron-heating rate by magnetic reconnection, the MAD model fails to reproduce the GeV data for the majority of our sample. This indicates that the electron-heating rate is crucial. We also apply the MAD model to Sagittarius A* (Sgr A*) and find that GeV gamma rays observed at the Galactic center do not come from the MAD of Sgr A*. We estimate the cosmic ray (CR) intensity from Sgr A*, but it is too low to explain the high-energy CR intensity on Earth.

  43. Candidate Tidal Disruption Event AT2019fdr Coincident with a High-Energy Neutrino Peer-reviewed

    Reusch, S., Stein, R., Kowalski, M., Van Velzen, S., Franckowiak, A., Lunardini, C., Murase, K., Winter, W., Miller-Jones, J.C.A., Kasliwal, M.M., Gilfanov, M., Garrappa, S., Paliya, V.S., Ahumada, T., An, , S., Barbarino, C., Bellm, E.C., Brinnel, V., Buson, S., Cenko, S.B., Coughlin, M.W., De, K., Dekany, R., Frederick, S., Gal-Yam, A., Gezari, S., Giroletti, M., Graham, M.J., Karambelkar, V., Kimura, S.S., Kong, A.K.H., Kool, E.C., Laher, R.R., Medvedev, P., Necker, J., Nordin, J., Perley, D.A., Rigault, M., Rusholme, B., Schulze, S., Schweyer, T., Singer, L.P., Sollerman, J., Strotjohann, N.L., Sunyaev, R., Van Santen, J., Walters, R., Zhang, B.T., Zimmerman, E.

    Physical Review Letters　128　(22)　2022/06/03

    Publisher: American Physical Society (APS)

    DOI： 10.1103/PhysRevLett.128.221101 　

    ISSN： 1079-7114 0031-9007

    eISSN： 1079-7114

  44. Can Stellar-mass Black Hole Growth Disrupt Disks of Active Galactic Nuclei? The Role of Mechanical Feedback Peer-reviewed

    Hiromichi Tagawa, Shigeo S. Kimura, Zoltán Haiman, Rosalba Perna, Hidekazu Tanaka, Imre Bartos

    The Astrophysical Journal　927　(1)　41-41　2022/03/01

    DOI： 10.3847/1538-4357/ac45f8 　

    ISSN： 0004-637X

    eISSN： 1538-4357

  45. Neutrinos from Gamma-ray Bursts Invited

    Kimura, Shigeo S.

    The Astrophysical Journal Letters　2022/02

    Publisher: arXiv e-prints

    ISSN： 2041-8205

    eISSN： 2041-8213

    More details Close

    Abstract We discuss implications that can be obtained by searches for neutrinos from the brightest gamma-ray burst (GRB), GRB 221009A. We derive constraints on GRB model parameters such as the cosmic-ray loading factor and dissipation radius, taking into account both neutrino spectra and effective areas. The results are strong enough to constrain proton acceleration near the photosphere, and we find that the single burst limits are comparable to those from stacking analysis. Quasi-thermal neutrinos from subphotospheres and ultra-high-energy neutrinos from external shocks are not yet constrained. We show that GeV–TeV neutrinos originating from neutron collisions are detectable, and urge dedicated analysis on these neutrinos with DeepCore and IceCube as well as ORCA and KM3NeT.

  46. High-energy Neutrinos from Magnetized Coronae of Active Galactic Nuclei and Prospects for Identification of Seyfert Galaxies and Quasars in Neutrino Telescopes Peer-reviewed

    Kheir, ish, A., Murase, K., Kimura, S.S.

    Astrophysical Journal　922　(1)　45-45　2021/11/18

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/ac1c77 　

    ISSN： 1538-4357 0004-637X

    eISSN： 1538-4357

  47. Multiwavelength Emission from Magnetically Arrested Disks around Isolated Black Holes Peer-reviewed

    Kimura, S.S., Kashiyama, K., Hotokezaka, K.

    Astrophysical Journal Letters　922　(1)　L15-L15　2021/11/18

    Publisher: American Astronomical Society

    DOI： 10.3847/2041-8213/ac35dc 　

    ISSN： 2041-8213 2041-8205

    eISSN： 2041-8213

  48. Soft gamma rays from low accreting supermassive black holes and connection to energetic neutrinos Peer-reviewed

    Kimura, S.S., Murase, K., M{\'e}sz{\'a}ros, P.

    Nature Communications　12　(1)　5615-5615　2021/09/23

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41467-021-25111-7 　

    ISSN： 2041-1723

    eISSN： 2041-1723

  49. Outflow Bubbles from Compact Binary Mergers Embedded in Active Galactic Nuclei: Cavity Formation and the Impact on Electromagnetic Counterparts Peer-reviewed

    Shigeo S. Kimura, Kohta Murase, Imre Bartos

    Astrophys.J.　916　(2)　111-111　2021/08/04

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/ac0535 　

    ISSN： 1538-4357 0004-637X

    eISSN： 1538-4357

  50. Magnetically Arrested Disks in Quiescent Black Hole Binaries: Formation Scenario, Observable Signatures, and Potential PeVatrons Peer-reviewed

    Shigeo S. Kimura, Takahiro Sudoh, Kazumi Kashiyama, Norita Kawanaka

    Astrophys.J.　915　(1)　31-31　2021/07/01

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/abff58 　

    ISSN： 1538-4357 0004-637X

    eISSN： 1538-4357

  51. Post-Merger Jets from Supermassive Black Hole Coalescences as Electromagnetic Counterparts of Gravitational Wave Emission Peer-reviewed

    Chengchao Yuan, Kohta Murase, B. Theodore Zhang, Shigeo S. Kimura, Mészáros, Peter

    Astrophys.J.Lett.　911　(1)　L15-L15　2021/04/15

    Publisher: American Astronomical Society

    DOI： 10.3847/2041-8213/abee24 　

    ISSN： 2041-8213 2041-8205

    eISSN： 2041-8213

  52. External Inverse-Compton Emission Associated with Extended and Plateau Emission of Short Gamma-Ray Bursts: Application to GRB 160821B Peer-reviewed

    B. Theodore Zhang, Kohta Murase, Chengchao Yuan, Shigeo S. Kimura, Peter Meszaros

    Astrophys.J.Lett.　908　(2)　L36-L36　2021/02/22

    Publisher: American Astronomical Society

    DOI： 10.3847/2041-8213/abe0b0 　

    ISSN： 2041-8213 2041-8205

    eISSN： 2041-8213

  53. Hadronic High-energy Emission from Magnetically Arrested Disks in Radio Galaxies Peer-reviewed

    Shigeo S. Kimura, Kenji Toma

    Astrophys.J.　905　(2)　178-178　2020/12/28

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/abc343 　

    ISSN： 1538-4357 0004-637X

    eISSN： 1538-4357

  54. Deciphering the Origin of the GeV–TeV Gamma-Ray Emission from SS 433 Peer-reviewed

    Shigeo S. Kimura, Kohta Murase, Peter Meszaros

    Astrophys.J.　904　(2)　188-188　2020/12/03

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/abbe00 　

    ISSN： 1538-4357 0004-637X

    eISSN： 1538-4357

  55. High-Energy Neutrino and Gamma-Ray Emission from Tidal Disruption Events Peer-reviewed

    Kohta Murase, Shigeo S. Kimura, B. Theodore Zhang, Foteini Oikonomou, Maria Petropoulou

    Astrophys.J.　902　(2)　108-108　2020/10/16

    Publisher: American Astronomical Society

    DOI： 10.3847/1538-4357/abb3c0 　

    ISSN： 1538-4357 0004-637X

    eISSN： 1538-4357

  56. High-energy neutrino emission subsequent to gravitational wave radiation from supermassive black hole mergers Peer-reviewed

    Yuan, C., Murase, K., Kimura, S.S., M{\'e}sz{\'a}ros, P.

    Physical Review D　102　(8)　2020/10/12

    Publisher: American Physical Society ({APS})

    DOI： 10.1103/PhysRevD.102.083013 　

    ISSN： 2470-0029 2470-0010

    eISSN： 2470-0029

  57. Hidden Cores of Active Galactic Nuclei as the Origin of Medium-Energy Neutrinos: Critical Tests with the MeV Gamma-Ray Connection Peer-reviewed

    Murase, Kohta, Kimura, Shigeo S., Meszaros, Peter

    Phys.Rev.Lett.　125　(1)　011101-011101　2020/06/30

    Publisher: American Physical Society (APS)

    DOI： 10.1103/PhysRevLett.125.011101 　

    ISSN： 1079-7114 0031-9007

    eISSN： 1079-7114

  58. Linking extended and plateau emissions of short gamma-ray bursts Peer-reviewed

    Matsumoto, T., Kimura, S.S., Murase, K., M{\'e}sz{\'a}ros, P.

    Monthly Notices of the Royal Astronomical Society　493　(1)　783-791　2020/03/21

    Publisher: Oxford University Press ({OUP})

    DOI： 10.1093/mnras/staa305 　

    ISSN： 1365-2966 0035-8711

  59. Upscattered Cocoon Emission in Short Gamma-Ray Bursts as High-energy Gamma-Ray Counterparts to Gravitational Waves Peer-reviewed

    Shigeo S. Kimura, Kohta Murase, Kunihito Ioka, Shota Kisaka, Ke Fang, Peter Mészáros

    The Astrophysical Journal　887　(1)　L16-L16　2019/12/10

    Publisher: American Astronomical Society

    DOI： 10.3847/2041-8213/ab59e1 　

    ISSN： 2041-8205

    eISSN： 2041-8213

  60. Multimessenger tests of cosmic-ray acceleration in radiatively inefficient accretion flows Peer-reviewed

    Kimura, Shigeo S., Murase, Kohta, Mészáros, Peter

    Phys.Rev.D　100　(8)　083014-083014　2019/10/19

    Publisher: American Physical Society (APS)

    DOI： 10.1103/PhysRevD.100.083014 　

    ISSN： 2470-0029 2470-0010

    eISSN： 2470-0029

  61. Acceleration and Escape Processes of High-energy Particles in Turbulence inside Hot Accretion Flows Peer-reviewed

    Kimura, Shigeo S., Tomida, Kengo, Murase, Kohta

    Mon.Not.Roy.Astron.Soc.　485　(1)　163-178　2019/05/01

    DOI： 10.1093/mnras/stz329 　

    ISSN： 1365-2966 0035-8711

  62. High-energy emissions from neutron star mergers

    Shigeo S. Kimura

    EPJ Web of Conferences　210　03001-03001　2019

    Publisher: EDP Sciences

    DOI： 10.1051/epjconf/201921003001 　

    eISSN： 2100-014X

    More details Close

    In 2017, LIGO-Virgo collaborations reported detection of the first neutron star merger event, GW170817, which is accompanied by electromagnetic counterparts from radio to gamma rays. Although high-energy neutrinos were not detected from this event, mergers of neutron stars are expected to produce such high-energy particles. Relativistic jets are launched when neutron stars merge. If the jets contain protons, they can emit high-energy neutrinos through photomeson production. In addition, neutron star mergers produce massive and fast ejecta, which can be a source of Galactic high-energy cosmic rays above the knee. We briefly review what we learned from the multi-messenger event, GW170817, and discuss prospects for multi-messenger detections and hadronic cosmic-ray production related to the neutron star mergers.

  63. Delayed jet breakouts from binary neutron star mergers Peer-reviewed

    Matsumoto, Tatsuya, Shigeo S. Kimura

    Astrophys.J.Lett.　866　(2)　L16　2018/10/12

    DOI： 10.3847/2041-8213/aae51b 　

    ISSN： 2041-8213 2041-8205

  64. Super-knee Cosmic Rays from Galactic Neutron Star Merger Remnants Peer-reviewed

    Kimura, S.S., Murase, K., M{\'e}sz{\'a}ros, P.

    Astrophysical Journal　866　(1)　51-51　2018/10/10

    DOI： 10.3847/1538-4357/aadc0a 　

    ISSN： 1538-4357 0004-637X

  65. Transejecta high-energy neutrino emission from binary neutron star mergers Peer-reviewed

    Kimura Shigeo S, Murase Kohta, Bartos Imre, Ioka Kunihito, Heng Ik Siong, Mészáros Peter

    Phys.Rev.D　98　(4)　043020　2018/08

    DOI： 10.1103/PhysRevD.98.043020 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  66. Low-luminosity gamma-ray bursts as the sources of ultrahigh-energy cosmic ray nuclei Peer-reviewed

    B. Theodore Zhang, Kohta Murase, Shigeo S. Kimura, Shunsaku Horiuchi, Peter Mészáros

    Physical Review D　97　(8)　083010　2018/04/23

    Publisher: American Physical Society

    DOI： 10.1103/PhysRevD.97.083010 　

    ISSN： 2470-0029 2470-0010

  67. Double Neutron Star Mergers and Short Gamma-ray Bursts: Long-lasting High-energy Signatures and Remnant Dichotomy Peer-reviewed

    Kohta Murase, Michael W. Toomey, Ke Fang, Foteini Oikonomou, Shigeo S. Kimura, Kenta Hotokezaka, Kazumi Kashiyama, Kunihito Ioka, Peter Mészáros

    Astrophysical Journal　854　(1)　60　2018/02/10

    Publisher: Institute of Physics Publishing

    DOI： 10.3847/1538-4357/aaa48a 　

    ISSN： 1538-4357 0004-637X

  68. Ultrahigh-energy cosmic-ray nuclei from black hole jets: Recycling galactic cosmic rays through shear acceleration Peer-reviewed

    Shigeo S. Kimura, Kohta Murase, B. Theodore Zhang

    Physical Review D　97　(2)　023026　2018/01/29

    Publisher: American Physical Society

    DOI： 10.1103/PhysRevD.97.023026 　

    ISSN： 2470-0029 2470-0010

  69. Outflow-driven Transients from the Birth of Binary Black Holes. II. Primary-induced Accretion Transients Peer-reviewed

    Shigeo S. Kimura, Kohta Murase, Peter Meszaros

    ASTROPHYSICAL JOURNAL　851　(1)　53　2017/12

    DOI： 10.3847/1538-4357/aa988b 　

    ISSN： 0004-637X

    eISSN： 1538-4357

  70. Outflow-driven Transients from the Birth of Binary Black Holes. I. Tidally Locked Secondary Supernovae Peer-reviewed

    Shigeo S. Kimura, Kohta Murase, Peter Meszaros

    ASTROPHYSICAL JOURNAL　851　(1)　52　2017/12

    DOI： 10.3847/1538-4357/aa989b 　

    ISSN： 0004-637X

    eISSN： 1538-4357

  71. High-energy Neutrino Emission from Short Gamma-Ray Bursts: Prospects for Coincident Detection with Gravitational Waves Peer-reviewed

    Shigeo S. Kimura, Kohta Murase, Peter Meszaros, Kenta Kiuchi

    ASTROPHYSICAL JOURNAL LETTERS　848　(1)　L4　2017/10

    DOI： 10.3847/2041-8213/aa8d14 　

    ISSN： 2041-8205

    eISSN： 2041-8213

  72. Sagittarius A* as an origin of the Galactic PeV cosmic rays? Peer-reviewed

    Yutaka Fujita, Kohta Murase, Shigeo S. Kimura

    JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS　04　(4)　037　2017/04

    DOI： 10.1088/1475-7516/2017/04/037 　

    ISSN： 1475-7516

  73. Evolution of an accretion disc in binary black hole systems Peer-reviewed

    Shigeo S. Kimura, Sanemichi Z. Takahashi, Kenji Toma

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY　465　(4)　4406-4413　2017/03

    DOI： 10.1093/mnras/stw3036 　

    ISSN： 0035-8711

    eISSN： 1365-2966

  74. From birth to death of protoplanetary discs: modelling their formation, evolution and dispersal Peer-reviewed

    Shigeo S. Kimura, Masanobu Kunitomo, Sanemichi Z. Takahashi

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY　461　(2)　2257-2265　2016/09

    DOI： 10.1093/mnras/stw1531 　

    ISSN： 0035-8711

    eISSN： 1365-2966

  75. Turbulent cosmic ray reacceleration and the curved radio spectrum of the radio relic in the Sausage Cluster Peer-reviewed

    Yutaka Fujita, Hiroki Akamatsu, Shigeo S. Kimura

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN　68　(3)　34　2016/06

    DOI： 10.1093/pasj/psw022 　

    ISSN： 0004-6264

    eISSN： 2053-051X

  76. STOCHASTIC PARTICLE ACCELERATION IN TURBULENCE GENERATED BY MAGNETOROTATIONAL INSTABILITY Peer-reviewed

    Shigeo S. Kimura, Kenji Toma, Takeru K. Suzuki, Shu-ichiro Inutsuka

    ASTROPHYSICAL JOURNAL　822　(2)　88　2016/05

    DOI： 10.3847/0004-637X/822/2/88 　

    ISSN： 0004-637X

    eISSN： 1538-4357

  77. Diffuse gamma-ray emission from the Galactic center and implications of its past activities Peer-reviewed

    Yutaka Fujita, Shigeo S. Kimura, Kohta Murase

    Proceedings of the International Astronomical Union　11　214-217　2016

    Publisher: Cambridge University Press

    DOI： 10.1017/S1743921316011807 　

    ISSN： 1743-9221 1743-9213

  78. Hadronic origin of multi-TeV gamma rays and neutrinos from low-luminosity active galactic nuclei: Implications of past activities of the Galactic center Peer-reviewed

    Yutaka Fujita, Shigeo S. Kimura, Kohta Murase

    Physical Review D - Particles, Fields, Gravitation and Cosmology　92　(2)　2015/07/06

    Publisher: American Physical Society

    DOI： 10.1103/PhysRevD.92.023001 　

    ISSN： 1550-2368 1550-7998

  79. NEUTRINO AND COSMIC-RAY EMISSION AND CUMULATIVE BACKGROUND FROM RADIATIVELY INEFFICIENT ACCRETION FLOWS IN LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI Peer-reviewed

    Shigeo S. Kimura, Kohta Murase, Kenji Toma

    ASTROPHYSICAL JOURNAL　806　(2)　159　2015/06

    DOI： 10.1088/0004-637X/806/2/159 　

    ISSN： 0004-637X

    eISSN： 1538-4357

  80. The role of the inner disk in mass accretion to the star in the early phase of star formation Peer-reviewed

    Takuya Ohtani, Shigeo S. Kimura, Toru Tsuribe, Eduard I. Vorobyov

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN　66　(6)　112　2014/12

    DOI： 10.1093/pasj/psu098 　

    ISSN： 0004-6264

    eISSN： 2053-051X

  81. Effect of lift force on the aerodynamics of dust grains in the protoplanetary disk Peer-reviewed

    Masaki S. Yamaguchi, Shigeo S. Kimura

    EARTH PLANETS AND SPACE　66　132　2014/10

    DOI： 10.1186/1880-5981-66-132 　

    ISSN： 1880-5981

  82. EFFECTS OF HIGH-ENERGY PARTICLES ON ACCRETION FLOWS ONTO A SUPERMASSIVE BLACK HOLE Peer-reviewed

    Shigeo S. Kimura, Kenji Toma, Fumio Takahara

    ASTROPHYSICAL JOURNAL　791　(2)　100　2014/08

    DOI： 10.1088/0004-637X/791/2/100 　

    ISSN： 0004-637X

    eISSN： 1538-4357

  83. Conditions of Gravitational Instability in Protoplanetary Disks Peer-reviewed

    Shigeo S. Kimura, Toru Tsuribe

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN　64　(5)　116　2012/10

    DOI： 10.1093/pasj/64.5.116 　

    ISSN： 0004-6264

    eISSN： 2053-051X

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Misc. 8

  1. 高エネルギーニュートリノ観測 からの 2040 年代スペース天文学 への期待

    岩切 渉, 木村 成生

    天文月報　117　(9)　2024/08

  2. ブラックホール天体での宇宙線加速と高エネルギー放射 Invited

    木村成生

    天文月報　2023　(112)　637-646　2023/11

  3. 超巨大ブラックホール近傍から放射される高エネルギー粒子 Invited

    木村成生

    Isotope News　2022　(8)　2022/08

  4. 静穏な超巨大ブラックホールから放射される高エネルギー粒子

    木村成生

    FRIS News　13　2022/03

  5. 相対論的無衝突衝撃波での乱流ダイナモによる磁場増幅

    冨田沙羅, 大平豊, 木村成生, 富田賢吾, 當真賢二

    日本天文学会年会講演予稿集　2022　2022

    ISSN： 1347-0639

  6. ブラックホール降着流における高エネルギー現象

    木村成生

    日本物理学会誌　76　(12)　2021/12

  7. 静穏時のブラックホール連星での強磁場降着流の形成と電磁波・宇宙線放射

    木村成生, 須藤貴弘, 樫山和己, 川中宣太

    日本天文学会年会講演予稿集　2021　2021

    ISSN： 1347-0639

  8. 高エネルギー天体としての高温降着流

    木村成生

    天文月報　2017　(7)　2017/07

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Books and Other Publications 2

  1. 天文学者が1を知ると、宇宙は10の謎を投げかけてくる : 研究者たちが見ている宇宙の最前線

    田中, 雅臣, 津村, 耕司, 佐藤, 文衛, 前原, 裕之, 守屋, 堯, 樫山, 和己, 木村, 成生, 秋山, 和徳, 播金, 優一

    河出書房新社　2025/05

    ISBN: 9784309254838

  2. The Encyclopedia of Cosmology Set 2: Frontiers in Cosmology Volume 2: Neutrino Physics and Astrophysics

    Floyd W Stecker, Pedro A N, Machado, John M LoSecco, Francis Halzen, Ali Kheirandish, Steven W Barwick, Christian Glaser, John F Krizmanic, George M Fuller, W C Haxton, E B Grohs, Shigeo S Kimura, Kohta Murase, Todor Stanev

    2023/11

    ISBN: 9789811289699

Presentations 62

  1. Stellar-mass Black Holes as Galactic PeVatrons International-presentation Invited

    Shigeo Kimura

    Tokyo PeVatron Workshop　2026/04/21

  2. Theoretical Models for Galactic PeVatrons Invited

    Shigeo Kimura

    2026/03/05

  3. Isolated Black Holes as Potential PeVatrons International-presentation

    Shigeo Kimura

    YKIS2026: Black Holes and Neutron Stars with Multi-Messengers　2026/02/09

  4. Galactic Stellar-mass Black Holes as Potential PeVatrons International-presentation Invited

    Shigeo Kimura

    MeV–PeV Frontiers: New Perspectives in Gamma-Ray Astronomy and Particle Acceleration　2025/12/16

  5. Subaru observations for IC230724A International-presentation

    Shigeo Kimura

    Annual Conference on Multi-messenger Astrophysics 2025　2025/11/19

  6. Which Source Classes Can We Confidently Rule Out? International-presentation Invited

    Shigeo Kimura

    The 22nd meeting of the AAS High Energy Astrophysics Division (HEAD 22)　2025/10/14

  7. Non-thermal Phenomena in Strongly Magnetized Accretion Flows around Black Holes International-presentation Invited

    Shigeo Kimura

    9th Asia-Pacific Conference on Plasma Physics (AAPPS-DPP 2025)　2025/09/24

  8. Theoretical Modeling for Galactic PeVatrons and Super-knee Cosmic-ray Sources International-presentation Invited

    Shigeo Kimura

    GCOS Workshop　2025/09/10

  9. 宇宙ニュートリノ追観測による電磁波対応天体探索

    木村成生

    Exploring Extreme Transients: Frontiers in the Early Universe and Time-Domain Astronomy　2025/08/07

  10. TeV-PeV gamma-ray emissions from Galactic Stellar-mass Black Holes International-presentation Invited

    Shigeo Kimura

    2nd LHAASO Symposium　2025/03/22

  11. Magnetic Reconnection around Black Holes and Multi-wavelength Emission Modeling from Them International-presentation Invited

    Shigeo Kimura

    International Workshop on Magnetic Reconnection in Space, Solar, Astrophysical, and Laboratory Plasmas (MR2025)　2025/03/12

  12. ニュートリノと X 線で探る高エネルギー天体現象 Invited

    木村成生

    高宇連研究会 2025　2025/03/07

  13. 孤立ブラックホールからの電磁波放射

    木村成生

    ブラックホール探査研究会 2025　2025/03/04

  14. 相互作用駆動型超新星からのガンマ線・ニュートリノ放射

    木村成生

    理論懇シンポジウム2024　2024/12/25

  15. Pursuing Sources of Cosmic High-energy Neutrinos International-presentation Invited

    International Conference on Neutrinos and Dark Matter 2024 (NuDM-2024)　2024/12/13

  16. Progress of theoretical modeling on high-energy neutrino emission

    Shigeo Kimura

    Annual Conference on Multi-messenger Astrophysics 2024,　2024/11/19

  17. Physical processes for high-energy neutrino astrophysics Invited

    木村成生

    Workshop on theoretical modeling of neutrino-emitting objects 2024　2024/11/06

  18. 輻射流体計算を基にした相互作用駆動型超新星からのガンマ線・ニュートリノ放射

    木村成生

    高エネルギー宇宙物理学研究会 2024　2024/10/21

  19. 超巨大ブラックホール周囲からの高エネルギーニュートリノ放射 Invited

    木村成生

    Exploring Extreme Transients: Emerging Frontiers and Challenges　2024/08/06

  20. 2nd-order Fermi Acceleration Model in AGN Accretion Flows International-presentation

    Shigeo Kimura

    AMES Workshop　2024/07/02

  21. Magnetic reconnection in radio galaxies: mass loading onto relativistic jets and multi-wavelength emission International-presentation Invited

    Shigeo Kimura

    UJI Reconnection Workshop 2024　2024/06/13

  22. Optical Follow-up Observations to Cosmic Neutrino Events in 2030s International-presentation

    Shigeo Kimura

    ELT Science in Light of JWST Asia, Sendai　2024/06/05

  23. Non-thermal emissions from accretion flows: Neutrinos from AGN and multi-wavelength signatures from isolated black holes International-presentation Invited

    Shigeo Kimura

    High-energy Astrophysics/Compact Object Mini-Workshop at TDLI　2024/05/17

  24. High-energy Neutrinos from Binary Neutron-star Mergers International-presentation Invited

    Shigeo Kimura

    Dialog at Dream Field 2024 (DDF 2024)　2024/05/13

  25. 近傍セイファート銀河からのハドロン起源 MeV ガンマ線放射

    木村成生

    日本天文学会 2024 年春季年会　2024/03/11

  26. Magnetic Reconnection in Black Hole Magnetosphere International-presentation Invited

    Shigeo Kimura

    Black Hole Astrophysics with VLBI 2024　2024/02/14

  27. 星間空間を漂う孤立ブラックホールからの高エネルギー放射

    木村成生

    理論懇シンポジウム2023　2023/12/26

  28. Galactic Black Holes as PeVatrons and sub-PeV gamma-ray sources International-presentation Invited

    Shigeo Kimura

    The 32nd Texas Symposium on Relativistic Astrophysics　2023/12/13

  29. Brief overview of theoretical models on cosmic neutrino sources International-presentation

    Shigeo Kimura

    Annual Conference on Multi-messenger Astrophysics　2023/12/04

  30. 星間空間を漂う孤立ブラックホールが引き起こす多波長放射とその観測可能性 Invited

    木村成生

    京都大学宇宙物理学教室談話会　2023/12/01

  31. 動的なMRI乱流場中での宇宙線粒子の振る舞い

    木村成生

    高エネルギー宇宙物理学研究会 2023　2023/11/28

  32. 宇宙高エネルギーニュートリノ背景放射の起源 Invited

    木村成生

    マルチメッセンジャー天文学の展開　2023/11/01

  33. Particle Acceleration in Accretion Flows and Related High-energy Signatures International-presentation Invited

    Shigeo S. Kimura

    High Energy Phenomena in Relativistic Outflows (HEPRO VIII)　2023/10/25

  34. ニュートリノ放射天体の理論モデル Invited

    木村成生

    日本天文学会 2023 年秋季年会　2023/09/20

  35. 宇宙ニュートリノを用いた宇宙線起源天体の探索 Invited

    木村成生

    日本物理学会 2023 年秋季年会　2023/09/18

  36. 原始星フレアでの宇宙線生成とガンマ線放射

    木村成生

    宇宙線で繋ぐ文明・地球環境・太陽系・銀河 2023　2023/09/14

  37. Neutrino emission from accretion flows in active galactic nuclei International-presentation Invited

    Shigeo S. Kimura

    ICRC 2023 satellite workshop　2023/08/07

  38. High-energy neutrino emissions from the vicinity of supermassive black holes International-presentation

    Shigeo S. Kimura

    The 38th International Cosmic-Ray Conference 2023 (ICRC2023)　2023/07/31

  39. Magnetic Reconnection at Black-hole Magnetosphere International-presentation Invited

    Shigeo S. Kimura

    MR2023 Workshop on Magnetic Reconnection　2023/06/27

  40. Galactic Black Holes as PeVatrons International-presentation Invited

    Shigeo S. Kimura

    The 1st LHAASO Symposium　2023/05/31

  41. Neutrinos from accretion flows onto supermassive black holes International-presentation Invited

    Shigeo S. Kimura

    Physics & Astronomy Department Forum at University of Nevada Las Vegas　2023/05/05

  42. Magnetic Reconnection and Subsequent Emission from Stellar-mass Black Holes International-presentation Invited

    Shigeo S. Kimura

    Astro-Coffee talk at Institute of Advanced Study　2023/04/24

  43. Magnetic Reconnection in Black-hole Magnetosphere International-presentation Invited

    Shigeo S. Kimura

    Astroplasmas Seminar at Princeton University　2023/04/21

  44. Observable Signatures from Black Holes in Disks of Active Galactic Nuclei International-presentation Invited

    Shigeo S. Kimura

    Astro-Coffee talk at Institute of Advanced Study　2023/04/10

  45. Non-thermal processes in radiatively inefficient accretion flows International-presentation Invited

    Shigeo S. Kimura

    THEA Seminar at Columbia University　2023/04/07

  46. 銀河系外宇宙線と宇宙ニュートリノの起源について Invited

    木村成生

    第六回 空気シャワー観測による宇宙線の起源探索研究会　2023/03/27

  47. ブラックホール天体での宇宙線加速と高エネルギー放射 Invited

    木村成生

    日本天文学会 2023 年春季年会　2023/03/15

  48. Magnetic reconnection in Black Hole Magnetospheres Invited

    木村成生

    ブラックホールジェット・降着円盤・円盤風研究会 2023　2023/03/01

  49. Theory overview of multimessenger signatures from GRBs International-presentation Invited

    Shigeo S. Kimura

    NCfA Symposium 2023: The Path forward in Multimessenger Astrophysics　2023/02/23

  50. Exploring the plasma loading mechanism of radio jets launched from black holes Invited

    2022/12/27

  51. 太陽フレアからのガンマ線放射と原始星フレアからの非熱的放射

    木村成生

    第35回理論懇シンポジウム　2022/12/21

  52. High-energy Neutrino Emission from Accretion Flows Invited

    2022/12/05

  53. Exploring the plasma loading mechanism of radio jets launched from black holes Invited

    Shigeo S. Kimura

    VLBI Group Seminar at Max Planck Institute for Radio Astronomy　2022/11/24

  54. Non-thermal processes in Accretion flows Invited

    Shigeo S. Kimura

    IRCC-AFP Meeting 2022　2022/10/28

  55. 天体ニュートリノを用いた宇宙線起源天体の探索

    木村成生

    宇宙線で繋ぐ文明・地球環境・太陽系・銀河　2022/10/26

  56. PFS を用いた天体高エネルギーニュートリノ追観測

    木村成生

    PFS Community Meeting　2022/10/04

  57. ブラックホールジェットの地平面近傍の電波放射機構:Sgr A*で見えない理由

    木村成生

    日本天文学会2022年秋季年会　2022/09/14

  58. Gamma-ray and neutrino emission from radiatively inefficient accretion flows

    Shigeo S. Kimura

    TeV Particle Astrophysics 2022　2022/08/09

  59. ブラックホール降着流での高エネルギー現象 Invited

    木村成生

    相対論的現象で探る宇宙の進化II　2022/05/27

  60. 孤立ブラックホール周囲の強磁場降着流からの多波長放射とその観測可能性

    木村成生

    日本天文学会2022年春季年会　2022/03/02

  61. Cosmic Rays in Accretion Flows Invited

    Shigeo S. Kimura

    Computational Astrophysics Groups Seminar at Tsinghua University　2022/03/02

  62. Multi-wavelength emission from magnetically arrested disks

    Shigeo S. Kimura

    Black Hole Astrophysics with VLBI 2022　2022/02/08

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Research Projects 9

  1. 孤立ブラックホールからの多波長放射モデルの構築と探査手法の確立

    木村 成生

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(B)

    Institution: 東北大学

    2026/04 - 2029/03

  2. The creation of multimessenger astrophysics

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Transformative Research Areas (A)

    Institution: Chiba University

    2023/04/01 - 2028/03/31

  3. Theoretical study on multi-messenger signals from neutrino emitting astrophysical objects

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Transformative Research Areas (A)

    Institution: Tohoku University

    2023/04/01 - 2028/03/31

  4. ニュートリノ天文学で探る天体高エネルギー粒子の起源

    System: 学際融合グローバル研究者育成東北イニシアティブ

    Institution: 東北大学 学際科学フロンティア研究所

    2022/06 - 2027/03

  5. Cosmic-ray acceleration and neutrino production in black-hole accretion flows

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Early-Career Scientists

    Category: Grant-in-Aid for Early-Career Scientists

    Institution: Tohoku University

    2022/04 - 2027/03

  6. Exploration of high-energy astrophysical phenomena in star and planet formation processes

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: Tohoku University

    2021/04/05 - 2026/03/31

  7. マルチメッセンジャー天文学を用いた天体高エネルギー粒子起源の探求

    木村 成生

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 特別研究員奨励費

    Category: 特別研究員奨励費

    Institution: 東北大学

    2019/04/25 - 2022/03/31

    More details Close

    今年度は活動銀河核からの高エネルギー粒子放射と、短いガンマ線バースとの長期活動について現象論的な研究を行った。 ・活動銀河核降着流からの高エネルギー放射 活動銀河核中心部の高温プラズマでは、宇宙線陽子が電磁相互作用により加速される。加速された陽子は背景の物質と相互作用して高エネルギーニュートリノを放射する。我々は明るい活動銀河核と暗い活動銀河核との両方の場合に、ガンマ線放射とニュートリノ放射とを計算し、現在IceCube実験が観測している宇宙ニュートリノ背景放射を広いエネルギー範囲で再現できることを示した。また、近傍の活動銀河核から軟ガンマ線は計画中のガンマ線衛星やニュートリノ実験により検出可能であることも明らかにした。また、暗い活動銀河核からの軟ガンマ線は観測されている軟ガンマ線背景放射を自然に説明できる。 ・短いガンマ線バーストの長期活動 連星中性子星の合体事象は短いガンマ線バーストを引き起こし、同時に多量の噴出物質を撒き散らす。我々は合体時に生成された噴出物質からの光子供給を考慮に入れた上で短いガンマ線バースとの長期活動中のガンマ線放射を計算し、短いガンマ線バーストからの高エネルギーガンマ線が重力波に対するGeV-TeVガンマ線対応天体としてFermi衛星やCTAガンマ線望遠鏡により検出可能であることを示した。また、短いガンマ線バーストの長期活動は、100秒程度の長期放射と１万秒程度のプラトー放射の二つに区分される。我々は長期放射の明るさとスペクトルの情報を用いて、長期放射はローレンツ因子が10以上の相対論的なジェットから放射されていることを示した。さらに、プラトー放射は長期放射が即時放射のジェットに追いついた際に放射されるというモデルで無理なく説明できることも示した。

  8. High-Energy Emission as Probes of the Connection between Short Gamma-Ray Bursts and Neutron Star Mergers

    Offer Organization: NASA

    System: Fermi Guest Investigator Program Cycle 11

    2019/09 - 2020/08

  9. 原始惑星系円盤の重力不安定と分裂条件

    木村 成生

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 特別研究員奨励費

    Category: 特別研究員奨励費

    Institution: 大阪大学

    2013/04/01 - 2015/03/31

    More details Close

    惑星は生まれたばかりの恒星である原始星の周囲を取り囲む原始惑星系円盤の中で形成されると考えられている。その中で起こる固体微粒子の集積過程、円盤の力学的進化などは惑星形成過程を理解する上で非常に重要である。 生まれたての恒星である原始星は、原始星へ物質が降り積もることで重力エネルギーを解放して光っている。短時間のうちに明るさが急激に増える原始星もあり、この現象の起源として２つの有力な説がある。一つは円盤の外側の方で重力不安定により分裂したガスの塊が中心星に落ちるというものである。もう一つは円盤内部で磁気回転不安定が活性・不活性を繰り返すことで質量降着率の増減をつくるというものである。この二つの説は相反するものではないため、ガス塊が落ちてくるなかで磁気流体不安定がどうなるかを調べた。その結果、重力不安定と時期流体不安定の２つの現象が互いに関連し合って増光現象と結びついている可能性を提案した。 現在の固体惑星形成の標準モデルでは、原始惑星系円盤の中で運動する固体微粒子が衝突を繰り返して固体惑星へと成長すると考えられている。この固体粒子が衝突する際に、粒子が自転角運動量を持つ可能性がある。その場合には、固体粒子に揚力が働くため、運動が変化すると考えられる。そこで、我々は円盤中の固体微粒子に働く揚力の効果を調べた。まず、固体粒子に角運動量が供給され続けるかどうかを見積もり、大きくな粒子は回転は持続し、揚力が働きうるという結果を得た。粒子にどの程度の揚力が働くかを、運動方程式を解くことで調べた。その結果、原始惑星系円盤の特性によっては揚力が無視できない場合が存在する可能性がある。 中心天体周りの回転円盤の物理は原始惑星系円盤だけでなく、ブラックホールへの降着流でも見られる。高温降着流中での非熱的粒子の力学構造への影響やニュートリノ放射についても研究も行った。

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Teaching Experience 8

  1. High-energy Astrophysics　Tohoku University

  2. 高エネルギー宇宙物理学　千葉大学

  3. 高エネルギー宇宙物理学　京都大学

  4. 学問論演習　東北大学

  5. 相対論的天体物理学特論Ⅰ（高エネルギー天文学）　東北大学

  6. 学問論演習　Tohoku University Undergraduate (liberal arts)

  7. 学問論演習　東北大学

  8. 自然の科学　東北学院大学

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Social Activities 1

  1. 片平まつり 学際研（宇宙企画） 講演者

    2025/10/11 -