Revealing the nature of dark matter with the use of Subaru large spectroscopic survey and dynamical analysis for the Galactic dwarf satellites

• Project/Area Number: 18J00277
• Research Category: Grant-in-Aid for JSPS Fellows
• Allocation Type: Single-year Grants
• Section: 国内
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: The University of Tokyo
• Principal Investigator: 林 航平 東京大学, 東京大学宇宙線研究所, 特別研究員(PD)
• Project Period (FY): 2018-04-25 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 暗黒物質 / 銀河系矮小銀河 / すばる望遠鏡 / 冷たい暗黒物質理論 / すばる広視野多天体分光器

Outline of Annual Research Achievements

銀河系矮小銀河は暗黒物質が支配的な恒星系であるため、銀河を構成する星々は暗黒物質の重力ポテンシャルに従って運動している。よって、矮小銀河の恒星の動力学解析から暗黒物質分布を調べることができる。この分布は暗黒物質理論によってその振る舞いが異なることが知られている。つまり矮小銀河動力学解析から暗黒物質理論に対して、宇宙物理学的側面から制限を与えることが可能である。このような背景から本研究で注目したのが自己相互作用する暗黒物質(SIDM)理論である。SIDM理論は暗黒物質粒子同士の相互作用の強さによって、暗黒物質ハローの中心部構造が変わると予言されている。
本研究では、非常に暗く小さな矮小銀河(ultra-faint dwarf; UFD)に焦点をあて、その動力学解析から暗黒物質分布を制限することで、SIDM理論の相互作用の強さを調べた。その結果、相互作用の強さが先行研究で得られていた値よりも一桁以上小さいことがわかった。これはSIDM理論に対して最も強い観測的制限である。また、得られた制限の値は、現在のSIDM理論では説明できないほど小さく、この理論の問題点を指摘することができた。
2023年から観測が開始されるすばる広視野多天体分光器(PFS)では、銀河系矮小銀河の観測がメインサイエンスの１つとなっている。本研究ではPFS観測開始に向け、模擬データを用いた矮小銀河暗黒物質分布の決定精度について詳細な研究を行っている。カリフォルニア工科大学とジョンズ・ホプキンス大学の共同研究者の協力の下、コンタミネーションや観測的不定性を含めたより現実的な模擬データの作成に成功した。現在このデータを用いた詳細な動力学解析を行っており、PFS１視野の観測では暗黒物質分布を制限することは難しいことがわかった。更に解析を進め、少なくとも何視野以上必要なのか、その定量的評価を継続して行う。

Research Progress Status

令和2年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和2年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] ジョンズ・ホプキンス大学/カリフォルニア工科大学(米国)
• [Int'l Joint Research] クルチャトフ研究所(ロシア連邦)
• [Int'l Joint Research] ジョンズ・ホプキンス大学/カリフォルニア工科大学(米国)
• [Int'l Joint Research] 中国科学院国家天文台(中国)
• [Int'l Joint Research] カリフォルニア工科大学/ジョンズ・ホプキンス大学(米国)
• [Int'l Joint Research] 中国科学院国家天文台(中国)
• [Journal Article] N-body Self-consistent Stellar-halo Modeling of the Fornax Dwarf Galaxy (2021)
  • Author(s): Shchelkanova Galina、Hayashi Kohei、Blinnikov Sergei
  • Journal Title: The Astrophysical Journal Volume: 909 Issue: 2 Pages: 147-147
  • DOI: 10.3847/1538-4357/abdd24
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Narrowing the mass range of Fuzzy Dark Matter with Ultra-faint Dwarfs (2021)
  • Author(s): K. Hayashi, E G. M. Ferreira, Jowett Hei Yin Chan
  • Journal Title: The Astrophysical Journal Letters Volume: -
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation (2021)
  • Author(s): H. Abdalla et al
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2021 Issue: 02 Pages: 048-048
  • DOI: 10.1088/1475-7516/2021/02/048
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Constraining Primordial Black Holes with Dwarf Galaxy Heating (2021)
  • Author(s): Lu Philip、Takhistov Volodymyr、Gelmini Graciela B.、Hayashi Kohei、Inoue Yoshiyuki、Kusenko Alexander
  • Journal Title: The Astrophysical Journal Volume: 908 Issue: 2 Pages: L23-L23
  • DOI: 10.3847/2041-8213/abdcb6
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Probing dark matter self-interaction with ultrafaint dwarf galaxies (2021)
  • Author(s): Hayashi Kohei、Ibe Masahiro、Kobayashi Shin、Nakayama Yuhei、Shirai Satoshi
  • Journal Title: Physical Review D Volume: 103 Issue: 2 Pages: 023017-023017
  • DOI: 10.1103/physrevd.103.023017
  • Peer Reviewed / Open Access
• [Journal Article] J-factor estimation of Draco, Sculptor, and Ursa Minor dwarf spheroidal galaxies with the member/foreground mixture model (2020)
  • Author(s): Horigome Shun-ichi、Hayashi Kohei、Ibe Masahiro、Ishigaki Miho N、Matsumoto Shigeki、Sugai Hajime
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 499 Issue: 3 Pages: 3320-3337
  • DOI: 10.1093/mnras/staa2909
  • NAID: 130008157053
  • Peer Reviewed
• [Journal Article] Diversity of Dark Matter Density Profiles in the Galactic Dwarf Spheroidal Satellites (2020)
  • Author(s): Hayashi Kohei、Chiba Masashi、Ishiyama Tomoaki
  • Journal Title: The Astrophysical Journal Volume: 904 Issue: 1 Pages: 45-63
  • DOI: 10.3847/1538-4357/abbe0a
  • Peer Reviewed / Open Access
• [Journal Article] Formation of massive globular clusters with dark matter and its implication on dark matter annihilation (2020)
  • Author(s): Wirth Henriette、Bekki Kenji、Hayashi Kohei
  • Journal Title: Monthly Notices of the Royal Astronomical Society: Letters Volume: 496 Issue: 1 Pages: L70-L74
  • DOI: 10.1093/mnrasl/slaa089
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] J-factor estimation of Draco, Sculptor and Ursa Minor dwarf spheroidal galaxies with the member/foreground mixture model (2020)
  • Author(s): S. Horigome, K. Hayashi, M. Ibe, M N. Ishigaki, S. Matsumoto, and H. Sugai
  • Journal Title: Astro-ph Volume: －
  • Open Access
• [Journal Article] Non-sphericity of ultralight-axion dark matter haloes in the Galactic dwarf spheroidal galaxies (2020)
  • Author(s): K. Hayashi, and I. Obata
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 491 Pages: 615-633
  • DOI: 10.1093/mnras/stz2950
  • Peer Reviewed / Open Access
• [Journal Article] Constraining dark matter annihilation with HSC low surface brightness galaxies (2020)
  • Author(s): Hashimoto Daiki、Macias Oscar、Nishizawa Atsushi J.、Hayashi Kohei、Takada Masahiro、Shirasaki Masato、Ando Shin'ichiro
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2020 Issue: 01 Pages: 059-059
  • DOI: 10.1088/1475-7516/2020/01/059
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Botes. IV. A new Milky Way satellite discovered in the Subaru Hyper Suprime-Cam Survey and implications for the missing satellite problem (2019)
  • Author(s): Homma Daisuke、Chiba Masashi、Komiyama Yutaka、Tanaka Masayuki、Okamoto Sakurako、Tanaka Mikito、Ishigaki Miho N、Hayashi Kohei、Arimoto Nobuo、Carlsten Scott G、Lupton Robert H、Strauss Michael A、Miyazaki Satoshi、Torrealba Gabriel、Wang Shiang-Yu、Murayama Hitoshi
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 71 Issue: 5 Pages: 1-13
  • DOI: 10.1093/pasj/psz076
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] The stellar halo of the Milky Way traced by blue horizontal-branch stars in the Subaru Hyper Suprime-Cam Survey (2019)
  • Author(s): Fukushima Tetsuya、Chiba Masashi、Tanaka Mikito、Hayashi Kohei、Homma Daisuke、Okamoto Sakurako、Komiyama Yutaka、Tanaka Masayuki、Arimoto Nobuo、Matsuno Tadafumi
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 71 Issue: 4 Pages: 1-16
  • DOI: 10.1093/pasj/psz052
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Non-sphericity of ultra-light axion dark matter halos in the Galactic dwarf spheroidal galaxies (2019)
  • Author(s): Hayashi Kohei、Ippei Obata
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: －
  • Open Access
• [Journal Article] Effects of mass models on dynamical mass estimate: the case of ultradiffuse galaxy NGC 1052-DF2 (2018)
  • Author(s): Hayashi Kohei、Inoue Shigeki
  • Journal Title: Monthly Notices of the Royal Astronomical Society: Letters Volume: 481 Issue: 1 Pages: L59-L63
  • DOI: 10.1093/mnrasl/sly162
  • Peer Reviewed
• [Journal Article] Dark halo structure in the Carina dwarf spheroidal galaxy: joint analysis of multiple stellar components (2018)
  • Author(s): Hayashi Kohei、Fabrizio Michele、Lokas Ewa L、Bono Giuseppe、Monelli Matteo、Dall’Ora Massimo、Stetson Peter B
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 481 Issue: 1 Pages: 250-261
  • DOI: 10.1093/mnras/sty2296
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] The Missing Satellite Problem Outside of the Local Group. I. Pilot Observation (2018)
  • Author(s): Tanaka Masayuki、Chiba Masashi、Hayashi Kohei、Komiyama Yutaka、Okamoto Takashi、Cooper Andrew P.、Okamoto Sakurako、Spitler Lee
  • Journal Title: The Astrophysical Journal Volume: 865 Issue: 2 Pages: 125-125
  • DOI: 10.3847/1538-4357/aad9fe
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Foreground effect on the J-factor estimation of ultrafaint dwarf spheroidal galaxies (2018)
  • Author(s): Ichikawa, K., Horigome, S., Ishigaki, M. N., Matsumoto, S., Ibe, M., Sugai, H., Hayashi, K.
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 479 Issue: 1 Pages: 64-74
  • DOI: 10.1093/mnras/sty1387
  • NAID: 130008148664
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] 銀河系矮小銀河ダークマター密度分布の多様性 (2021)
  • Author(s): 林航平
  • Organizer: 日本天文学会2021年春季年会
• [Presentation] Non-spherical dark halo structures and J-factor mapping for the Galactic dwarf spheroidals (2020)
  • Author(s): Kohei Hayashi
  • Organizer: KEK-Cosmo Joint Lectures and Workshop on “Dark Matter”
  • Int'l Joint Research
• [Presentation] 超低輝度矮小銀河を用いたSelf-interacting dark matter への制限 (2020)
  • Author(s): 林航平
  • Organizer: 第９回観測的宇宙論ワークショップ
• [Presentation] Milky Way science with HSC Northern-hemisphere Ultra Wide Survey (2020)
  • Author(s): 林航平
  • Organizer: Euclid衛星とすばる望遠鏡のシナジー
  • Invited
• [Presentation] 銀河系矮小銀河を用いたultra-light axion dark matterへの制限 (2020)
  • Author(s): 林航平
  • Organizer: 日本天文学会2020年春季年会
• [Presentation] Diversity of the central dark matter densities in the Galactic dwarf spheroidals (2020)
  • Author(s): 林航平
  • Organizer: Cosmic Acceleration
  • Int'l Joint Research
• [Presentation] Pseudo phase space density of dark matter halos in the dwarf spheroidals (2019)
  • Author(s): 林航平
  • Organizer: 6th Galaxy Evolution Workshop
• [Presentation] PFS, WFIRST, CTAのシナジーで迫る銀河系矮小銀河ダークマター研究の将来展望 (2019)
  • Author(s): 林航平
  • Organizer: 我が国の（近）赤外線広視野観測サイエンスの戦略と展望
• [Presentation] 銀河系矮小銀河コアカスプ問題の再検討 (2019)
  • Author(s): 林航平
  • Organizer: 第８回観測的宇宙論ワークショップ
• [Presentation] Galactic Archaeology: Unveiling the nature of dark matter (2019)
  • Author(s): 林航平
  • Organizer: Berkeley Week
• [Presentation] Ultralight axion dark matter and small-scale problem (2019)
  • Author(s): 林航平
  • Organizer: Two-day workshop: Axion Cosmology
  • Int'l Joint Research / Invited
• [Presentation] Dark matter distributions in the Galactic dwarf spheroidal galaxies (2019)
  • Author(s): 林航平
  • Organizer: Topics in Astroparticle and Underground Physics (TAUP) 2019
  • Int'l Joint Research
• [Presentation] Diversity of dark matter distributions in the Galactic dwarf satellites (2019)
  • Author(s): 林航平
  • Organizer: Subaru International Conference “Subaru Telescope 20th Anniversary”
  • Int'l Joint Research
• [Presentation] Dark matter in dwarf galaxies in the Subaru-PFS era (2019)
  • Author(s): 林航平
  • Organizer: Subaru International Conference “Subaru Telescope 20th Anniversary”
  • Int'l Joint Research
• [Presentation] Dark matter density profiles in the classical dwarf spheroidal galaxies in Milky Way (2019)
  • Author(s): 林航平
  • Organizer: 新学術シンポジウム「なぜ宇宙は加速するのか？-徹底的究明と将来への挑戦-」
• [Presentation] Non-sphericity of ultralight axion dark matter halos in the Galactic dwarf satellites (2019)
  • Author(s): 林航平
  • Organizer: Accelerating Universe in the Dark
  • Int'l Joint Research
• [Presentation] 銀河系矮小銀河の観測的不定性を考慮した暗黒物質分布推定 (2018)
  • Author(s): 林航平
  • Organizer: 日本天文学会２０１８年秋季年会
• [Presentation] Dark halo structures and star formation histories of the Galactic dwarf spheroidals (2018)
  • Author(s): 林航平
  • Organizer: Workshop in Galactic Archaeology with LAMOST and Subaru
• [Presentation] The universal dark halo scaling relation for the dwarf satellites (2018)
  • Author(s): 林航平
  • Organizer: 第５回銀河進化研究会
• [Presentation] Effects of mass models on dynamical mass estimate: the case for ultra diffuse galaxy NGC1052-DF2 (2018)
  • Author(s): 林航平
  • Organizer: 日本天文学会２０１８年秋季年会
• [Presentation] Universal dark halo scaling relation for the dwarf spheroidal galaxies (2018)
  • Author(s): 林航平
  • Organizer: The 8th KIAS workshop on cosmology and structure formation
  • Int'l Joint Research / Invited
• [Presentation] PFS survey simulations for GA targets (2018)
  • Author(s): 林航平
  • Organizer: The PFS 10th General Collaboration Meeting
  • Int'l Joint Research
• [Presentation] Update on the PFS-DSPH (2018)
  • Author(s): 林航平
  • Organizer: PFS Science Working Group meeting
  • Int'l Joint Research
• [Presentation] Robust estimate of dark matter distributions in the Galactic dwarf spheroidals (2018)
  • Author(s): 林航平
  • Organizer: TeV Particle Astrophysics 2018
  • Int'l Joint Research
• [Funded Workshop] Dark Matter Searches in the 2020s - At the crossroads of WIMP (2019)