銀河形成シミュレーションで迫るダークマターの正体

• Project Area: Why does the Universe accelerate? - Exhaustive study and challenge for the future -
• Project/Area Number: 16H01085
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: Hokkaido University
• Principal Investigator: 岡本 崇 北海道大学, 理学研究院, 講師 (50541893)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000); Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2016: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
• Keywords: 銀河形成 / ダークマター / 数値シミュレーション / フィードバック / 宇宙論 / シミュレーション / 宇宙物理 / 理論天文学

Outline of Annual Research Achievements

前年度に実装を終えた self-interacting dark matter (SIDM) を仮定した銀河形成シミュレーションを行うために、メッシュフリー流体コードに、ガス冷却、星形成、星の進化、大質量星からの紫外線や恒星風、超新星爆発による星間ガスの加熱、AGB 星、重力崩壊型及び Ia 型超新星爆発による化学進化等の銀河形成に重要な役割を果たす物理過程の実装を終えた。特に、加熱されたガスを多相モデルとして扱うことにより、数値分解能に依らず物理的に正しい結果を出すように超新星爆発等による星間ガスの加熱効果を実装した。様々な SIDM を仮定した銀河形成シミュレーションを行い cold dark matter (CDM) と比較する準備が整った。
関連して、ダークハローのポテンシャル構造が内部の銀河の星形成活動に及ぼす影響を高分解能の孤立銀河シミュレーションを用いて調べた。その結果、星形成の現場となるガス雲の形成にはシアー不安定性と重力不安定性が重要な役割を果たすことが明らかになった。
また、大質量星からの輻射が分子雲に与える影響を調べるためにダスト入りの輻射流体シミュレーションを行なった。その際、ダストとガスは強くカップルしているというしばしば用いられる仮定を外し、ダストとガスの相互作用とダストのサイズ分布を考慮した。その結果、大質量星近傍では輻射圧によりダストが優先的に外縁部に運ばれるため、dust cavity と呼ばれるダストのない領域が形成されることが分かった。

Research Progress Status

29年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

29年度が最終年度であるため、記入しない。

Research Products

• [Journal Article] The impact of galactic disc environment on star-forming clouds (2018)
  • Author(s): Nguyen, Ngan K.; Pettitt, Alex R.; Tasker, Elizabeth J.; Okamoto, Takashi
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 475 Issue: 1 Pages: 27-42
  • DOI: 10.1093/mnras/stx3143
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] The effect of radiation pressure on spatial distribution of dust inside HII regions (2017)
  • Author(s): Ishiki Shohei、Okamoto Takashi、Inoue Akio K.
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 474 Issue: 2 Pages: 1935-1943
  • DOI: 10.1093/mnras/stx2833
  • Peer Reviewed
• [Journal Article] Imprints of the super-Eddington accretion on the quasar clustering (2017)
  • Author(s): T.Oogi, M.Enoki,T.Ishiyama, M.Kobayashi, R.Makiya, M.Nagashima, T.Okamoto, H.Shirakata
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 471 Issue: 1 Pages: L21-L25
  • DOI: 10.1093/mnrasl/slx102
  • Peer Reviewed / Open Access
• [Journal Article] Theoretical Re-evaluations of Scaling Relations between SMBHs and Their Host Galaxies . 1. Effect of Seed BH Mass (2017)
  • Author(s): Hikari Shirakata, Toshihiro Kawaguchi, Takashi Okamoto, Ryu Makiya, Tomoaki Ishiyama, Yoshiki Matsuoka, Masahiro Nagashima, Motohiro Enoki, Taira Oogi, and Masakazu A. R. Kobayashi
  • Journal Title: Frontiers in Astronomy and Space Sciences Volume: 4
  • DOI: 10.3389/fspas.2017.00015
  • Peer Reviewed / Open Access
• [Journal Article] Theoretical Re-evaluations of Scaling Relations between SMBHs and Their Host Galaxies. 2. Importance of AGN Feedback Suggested by Stellar Age - Velocity Dispersion Relation (2017)
  • Author(s): Hikari Shirakata, Toshihiro Kawaguchi, Takashi Okamoto, and Tomoaki Ishiyama
  • Journal Title: Frontiers in Astronomy and Space Sciences Volume: 4
  • DOI: 10.3389/fspas.2017.00013
  • Peer Reviewed / Open Access
• [Journal Article] The metal enrichment of passive galaxies in cosmological simulations of galaxy formation (2017)
  • Author(s): Okamoto, Takashi; Nagashima, Masahiro; Lacey, Cedric G.; Frenk, Carlos S.
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 464 Issue: 4 Pages: 4866-4874
  • DOI: 10.1093/mnras/stw2729
  • NAID: 120006219984
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Radiation feedback in dusty clouds (2017)
  • Author(s): Ishiki, Shohei; Okamoto, Takashi
  • Journal Title: Monthly Notices of the Royal Astronomical Society: Letters Volume: 466 Issue: 1 Pages: L123-L127
  • DOI: 10.1093/mnrasl/slw253
  • NAID: 120006360086
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] The New Numerical Galaxy Catalog (ν^2GC): An Updated Semi-analytic Model of Galaxy and AGN with Large Cosmological N-body Simulations (2016)
  • Author(s): Ryu Makiya, Motohiro Enoki, Tomoaki Ishiyama, Masakazu A.R. Kobayashi, Masahiro Nagashima, Takashi Okamoto, Katsuya Okoshi, Taira Oogi, Hikari Shirakata
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 68 Issue: 2 Pages: 25-51
  • DOI: 10.1093/pasj/psw005
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Detection of an oxygen emission line from a high-redshift galaxy in the reionization epoch (2016)
  • Author(s): Inoue, Akio K.; Tamura, Yoichi; Matsuo, Hiroshi; Mawatari, Ken; Shimizu, Ikkoh; Shibuya, Takatoshi; Ota, Kazuaki; Yoshida, Naoki; Zackrisson, Erik; Kashikawa, Nobunari; Kohno, Kotaro; Umehata, Hideki; Hatsukade, Bunyo; Iye, Masanori; Matsuda, Yuichi; Okamoto, Takashi; Yamaguchi, Yuki
  • Journal Title: Science Volume: 352 Pages: 1559-1562
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Theoretical re-evaluations of the black hole mass-bulge mass relation - I. Effect of seed black hole mass (2016)
  • Author(s): Shirakata, Hikari; Kawaguchi, Toshihiro; Okamoto, Takashi; Makiya, Ryu; Ishiyama, Tomoaki; Matsuoka, Yoshiki; Nagashima, Masahiro; Enoki, Motohiro; Oogi, Taira; Kobayashi, Masakazu A. R.
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 461 Issue: 4 Pages: 4389-4394
  • DOI: 10.1093/mnras/stw1798
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Nebular line emission from z > 7 galaxies in a cosmological simulation: rest-frame UV to optical lines (2016)
  • Author(s): Shimizu, Ikkoh; Inoue, Akio K.; Okamoto, Takashi; Yoshida, Naoki
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 461 Issue: 4 Pages: 3563-3575
  • DOI: 10.1093/mnras/stw1423
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] Towards galaxy formation simulations of Milky Way satellites with alternative dark matter models (2018)
  • Author(s): Takashi Okamoto
  • Organizer: 新学術領域「なぜ宇宙は加速するのか？- 徹底的究明と将来への挑戦-」Why does the Universe accelerate?-Exhaustive study and challenge for the future
  • Int'l Joint Research / Invited
• [Presentation] 銀河形成シミュレーションによる星形成銀河の星形成率とガス流入・流出率 (2017)
  • Author(s): 岡本崇
  • Organizer: 日本天文学会
• [Presentation] Inflows and outflows in high-redshift simulated galaxies (2016)
  • Author(s): Takashi Okamoto
  • Organizer: ULTIMATE-Subaru science workshop 2016
  • Place of Presentation: 東京都三鷹市・国立天文台三鷹キャンパス
  • Year and Date: 2016-06-16
  • Int'l Joint Research / Invited