Theoretical Study on Formation of Supermassive Black Holes

• Project/Area Number: 17H01102
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Astronomy
• Research Institution: Tohoku University
• Principal Investigator: 大向 一行 東北大学, 理学研究科, 教授 (70390622)
• Co-Investigator(Kenkyū-buntansha): 細川 隆史 京都大学, 理学研究科, 准教授 (30413967) ; 大須賀 健 筑波大学, 計算科学研究センター, 教授 (90386508)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Project Status: Granted (Fiscal Year 2020)
• Budget Amount: ¥43,940,000 (Direct Cost: ¥33,800,000、Indirect Cost: ¥10,140,000); Fiscal Year 2021: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000); Fiscal Year 2020: ¥9,360,000 (Direct Cost: ¥7,200,000、Indirect Cost: ¥2,160,000); Fiscal Year 2019: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000); Fiscal Year 2018: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000); Fiscal Year 2017: ¥8,060,000 (Direct Cost: ¥6,200,000、Indirect Cost: ¥1,860,000)
• Keywords: 巨大ブラックホール / 宇宙初期天体 / 銀河形成 / 星形成 / 活動銀河核

Outline of Annual Research Achievements

種ブラックホール形成に関しての有力なシナリオは直接崩壊といわれる巨大なガスの塊から超大質量星が形成され、それが一般相対論的不安定性により重力崩壊を起こすものである。これが可能な条件として、これまでは外部からの強い紫外線輻射の照射および材料となるガスが始原組成であることが必要と考えられてきた。この条件は厳しすぎるため、形成される種ブラックホールの数が十分大きくはないという困難があった。そこで、その当否を調べるため、我々は重元素が少しある場合についても3次元シミュレーションにより形成条件を吟味したところ、重元素があっても太陽金属度の1/1000以下なら同様の直接崩壊により種ブラックホールが形成されることが見いだされた。
また、ブラックホールの降着成長に関して輻射流体シミュレーションを行った。巨大ブラックホール周りには降着円盤が存在するが、そこからの質量損失が大きいと、ブラックホールの成長が阻害されることとなる。そこで、吸収線駆動の円盤風に着目し、それによる質量損失率の中心ブラックホール質量およびガス重元素への依存性を解析した。その結果、ブラックホール質量が太陽の一億倍を超えるほど大きく、また重元素量が太陽近傍程度高くない限り、このような円盤風による質量損失は深刻ではないことが分かった。これは宇宙初期に観測されているような巨大ブラックホールの成長において、円盤風は大きな妨げとはならないことを意味する。

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

当初の研究計画と比べ特に大きな後れなく研究が遂行できている。

Strategy for Future Research Activity

これまでほぼ当初の研究計画どおり研究を遂行出来ているので、今後もこのペースを継続して当初計画を維持し、推進する予定である。

Research Products

• [Int'l Joint Research] Sapienza University of Rome(イタリア)
• [Int'l Joint Research] KIAA, Peking University(中国)
• [Int'l Joint Research] Columbia University(米国)
• [Int'l Joint Research] Sapienza University of Rome/Scuola Normale Superiore, Pisa(イタリア)
• [Int'l Joint Research] National Astronomical Observatories(中国)
• [Journal Article] Magnetohydrodynamic Simulations of a Plunging Black Hole into a Molecular Cloud (2019)
  • Author(s): Nomura Mariko、Oka Tomoharu、Yamada Masaya、Takekawa Shunya、Ohsuga Ken、Takahashi Hiroyuki R.、Asahina Yuta
  • Journal Title: The Astrophysical Journal Volume: 859 Pages: 29-29
  • DOI: 10.3847/1538-4357/aabe32
  • Peer Reviewed
• [Journal Article] Super-Eddington accretion of dusty gas onto seed black holes: metallicity-dependent efficiency of mass growth (2019)
  • Author(s): Toyouchi Daisuke , Hosokawa Takashi , Sugimura Kazuyuki , Nakatani Riouhei , Kuiper Rolf
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: - Pages: 2031-2043
  • DOI: 10.1093/mnras/sty3012
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Condition for dust evacuation from the first galaxies (2018)
  • Author(s): Fukushima Hajime , Yajima Hidenobu , Omukai Kazuyuki
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 477 Pages: 10711085-10711085
  • DOI: 10.1093/mnras/sty799
  • Peer Reviewed
• [Journal Article] Stunted accretion growth of black holes by combined effect of the flow angular momentum and radiation feedback (2018)
  • Author(s): Sugimura Kazuyuki , Hosokawa Takashi , Yajima Hidenobu , Inayoshi Kohei , Omukai Kazuyuki
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 478 Pages: 39613975-39613975
  • DOI: 10.1093/mnras/sty1298
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Condition for low-mass star formation in shock-compressed metal-poor clouds (2018)
  • Author(s): Nakauchi Daisuke , Omukai Kazuyuki , Schneider Raffaella
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 480 Pages: 10431056-10431056
  • DOI: 10.1093/mnras/sty1911
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Rapid growth of black holes accompanied with hot or warm outflows exposed to anisotropic super-Eddington radiation (2018)
  • Author(s): Takeo Eishun、Inayoshi Kohei、Ohsuga Ken、Takahashi Hiroyuki R、Mineshige Shin
  • Journal Title: Mon. Notices. Roy. Astron. Soc. Volume: 476 Pages: 673-673
  • DOI: 10.1093/mnras/sty264
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Systematic two-dimensional radiation-hydrodynamic simulations of super-Eddington accretion flow and outflow: Comparison with the slim disk model (2018)
  • Author(s): Kitaki, Takaaki; Mineshige, Shin; Ohsuga, Ken; Kawashima, Tomohisa
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 70 Pages: 108-108
  • DOI: 10.1093/pasj/psy110
  • Peer Reviewed
• [Journal Article] Radiation hydrodynamics simulations of the formation of direct-collapse supermassive stellar systems (2018)
  • Author(s): S. Chon, T. Hosokawa, N. Yoshida
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 475 Pages: 4104-4121
  • DOI: 10.1093/mnras/sty086
  • Peer Reviewed
• [Journal Article] Triggering the Formation of Direct Collapse Black Holes by Their Congeners (2017)
  • Author(s): Yue, Bin; Ferrara, Andrea; Pacucci, Fabio; Omukai, Kazuyuki
  • Journal Title: The Astrophysical Journal Volume: 838 Pages: 111-111
  • DOI: 10.3847/1538-4357/aa6627
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Rapid Black Hole Growth under Anisotropic Radiation Feedback (2017)
  • Author(s): Sugimura, Kazuyuki; Hosokawa, Takashi; Yajima, Hidenobu; Omukai, Kazuyuki
  • Journal Title: MNRAS Volume: 未定 Pages: 62-79
  • DOI: 10.1093/mnras/stx769
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Fates of the dense cores formed by fragmentation of filaments: do they fragment again or not? (2017)
  • Author(s): Sugimura Kazuyuki、Mizuno Yurina、Matsumoto Tomoaki、Omukai Kazuyuki
  • Journal Title: MNRAS Volume: 469 Pages: 4022-4033
  • DOI: 10.1093/mnras/stx1129
  • Peer Reviewed
• [Journal Article] Primordial protostars accreting beyond the ΩΓ-limit: radiation effect around the star-disc boundary (2017)
  • Author(s): Takahashi Sanemichi Z. , Omukai Kazuyuki
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 472 Pages: 532-541
  • DOI: 10.1093/mnras/stx1988
  • Peer Reviewed
• [Journal Article] Upper stellar mass limit by radiative feedback at low-metallicities: metallicity and accretion rate dependence (2017)
  • Author(s): Fukushima Hajime、Omukai Kazuyuki、Hosokawa Takashi
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 473 Pages: 4754-4772
  • DOI: 10.1093/mnras/stx2620
  • Peer Reviewed
• [Presentation] 宇宙初期の星形成におけるダストの役割 (2019)
  • Author(s): 大向一行
  • Organizer: 銀河の化学進化とダスト形成
  • Invited
• [Presentation] From First Stars to First Black Holes (2018)
  • Author(s): Kazuyuki Omukai
  • Organizer: The early growth of supermassive black holes
  • Int'l Joint Research / Invited
• [Presentation] Feedback from accreting seed black holes and progenitor stars (2018)
  • Author(s): Takashi Hosokawa
  • Organizer: The early growth of supermassive black holes
  • Int'l Joint Research / Invited
• [Presentation] Status Report of A03 in FY2018: Quest for BH binary (2018)
  • Author(s): Kazuyuki Omukai
  • Organizer: The Second annual symposium of the innovative area "Gravitational Wave Physics and Astronomy: Genesis"
  • Int'l Joint Research / Invited
• [Presentation] Radiation-MHD simulations of accretion flows and outflows around black holes and neutron stars (2018)
  • Author(s): Ken Ohsuga
  • Organizer: Max-Planck/Princeton Center for Plasma Physics Workshop
• [Presentation] Super-Eddington flows and spectra (2018)
  • Author(s): Ken Ohsuga
  • Organizer: ULTRA-LUMINOUS X-RAY PULSARS
• [Presentation] Understanding primordial star formation: Francesco's contribution (2017)
  • Author(s): Kazuyuki Omukai
  • Organizer: Francesco's Legacy: Star Formation in Space and Time
  • Int'l Joint Research / Invited
• [Book] ブラックホールをのぞいてみたら (2017)
  • Author(s): 大須賀 健
  • Total Pages: 256
  • Publisher: ＫＡＤＯＫＡＷＡ
  • ISBN: 9784041061848
• [Book] マルいアタマをもっとマルく！日能研クエスト 宇宙のふしぎ最前線！ 謎だらけの宇宙にいどむ (2017)
  • Author(s): 大須賀 健、日能研
  • Total Pages: 200
  • Publisher: 講談社
  • ISBN: 9784062206723