A method for identifying ionizing sources of reionization focusing on hyperfine structures of H and He

• Project/Area Number: 18K03699
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 16010:Astronomy-related
• Research Institution: Nagoya University
• Principal Investigator: Hasegawa Kenji 名古屋大学, 理学研究科, 特任助教 (20536627)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 宇宙再電離 / 輻射輸送 / 電波観測 / 再電離 / 超微細構造線 / 輻射輸送シミュレーション / 数値シミュレーション / 電波天文学 / 銀河形成

Outline of Final Research Achievements

First I have developed a cosmological radiative transfer code by which the distributions of ionized hydrogen and helium depending on the spectrum type of ionizing sources can be solved. The simulation results show that the spatial correlation between HI and HeII strongly depends on the type of ionizing sources.
Furthermore we have developed a sub-grid model of the first stars for simulations of reionization.
In addition, we have put the most strong upper limit on the 21cm power spectrum during the epoch of reionization by observations with MWA.

Academic Significance and Societal Importance of the Research Achievements

自身が開発したシミュレーションコードで得た結果は、将来の観測との直接比較によりこれまで決定的な証拠がなかった宇宙再電離の光源種別を判別できると期待している。またシミュレーション結果は多くの研究者と共有しており、すでに様々な宇宙再電離の観測との比較や今後の観測予言に用いられており今後もこの分野の研究に大きく貢献できると考えている。
MWAの観測で得た21cmパワースペクトルの上限は、すでにいくつかの再電離モデルを棄却しており、その意味で学術的意義は大きい。さらに今後の次世代電波望遠鏡での21cm線の直接検出へ向けた問題点の洗い出しができた点においても重要な役割を果たした。

Research Products

• [Int'l Joint Research] University of Sydney/University of Melbourne(オーストラリア)
• [Journal Article] Epoch of reionization power spectrum limits from Murchison Widefield Array data targeted at EoR1 field (2021)
  • Author(s): Rahimi M., et al.
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 508 Issue: 4 Pages: 5954-5971
  • DOI: 10.1093/mnras/stab2918
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Constraining the 21 cm brightness temperature of the IGM at z = 6.6 around LAEs with the murchison widefield array (2021)
  • Author(s): Trott, C. M. ; Jordan, C. H. ; Line, J. L. B., et al.,
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 507 Issue: 1 Pages: 772-780
  • DOI: 10.1093/mnras/stab2235
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A new MWA limit on the 21 cm power spectrum at redshifts 13-17 (2021)
  • Author(s): Yoshiura, S. ; Pindor, B. ; Line, J. L. B., et al.,
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 505 Issue: 4 Pages: 4775-4790
  • DOI: 10.1093/mnras/stab1560
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Predicting 21?cm-line map from Lyman-α emitter distribution with generative adversarial networks (2021)
  • Author(s): Yoshiura Shintaro、Shimabukuro Hayato、Hasegawa Kenji、Takahashi Keitaro
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 506 Issue: 1 Pages: 357-371
  • DOI: 10.1093/mnras/stab1718
  • Peer Reviewed
• [Journal Article] Modelling population III stars for seminumerical simulations (2021)
  • Author(s): Tanaka Toshiyuki、Hasegawa Kenji
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 502 Issue: 1 Pages: 463-471
  • DOI: 10.1093/mnras/stab072
  • Peer Reviewed
• [Journal Article] The impact of tandem redundant/sky-based calibration in MWA Phase II data analysis (2020)
  • Author(s): Zhang Zheng et al.
  • Journal Title: Publications of the Astronomical Society of Australia Volume: 37
  • DOI: 10.1017/pasa.2020.37
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] The 21-cm signals from ultracompact minihaloes as a probe of primordial small-scale fluctuations (2020)
  • Author(s): Furugori Kunihiko、Abe Katsuya T、Tanaka Toshiyuki、Hashimoto Daiki、Tashiro Hiroyuki、Hasegawa Kenji
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 494 Issue: 3 Pages: 4334-4342
  • DOI: 10.1093/mnras/staa1033
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Detectability of 21-cm signal during the epoch of reionization with 21-cm-Lyman-α emitter cross-correlation ? III. Model dependence (2020)
  • Author(s): Kubota Kenji、Inoue Akio K、Hasegawa Kenji、Takahashi Keitaro
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 494 Issue: 3 Pages: 3131-3140
  • DOI: 10.1093/mnras/staa979
  • Peer Reviewed
• [Journal Article] Deep multiredshift limits on Epoch of Reionization 21?cm power spectra from four seasons of Murchison Widefield Array observations (2020)
  • Author(s): Torotti Cathryn M., Kenji Hasegawa et al.
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 493 Issue: 4 Pages: 4711-4727
  • DOI: 10.1093/mnras/staa414
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Discrimination of heavy elements originating from Pop?III stars in z?= 3 intergalactic medium (2019)
  • Author(s): Kirihara Takanobu、Hasegawa Kenji、Umemura Masayuki、Mori Masao、Ishiyama Tomoaki
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 491 Issue: 3 Pages: 4387-4395
  • DOI: 10.1093/mnras/stz3376
  • NAID: 120007132819
  • Peer Reviewed / Open Access
• [Journal Article] First Season MWA Phase II Epoch of Reionization Power Spectrum Results at Redshift 7 (2019)
  • Author(s): Li W., Kenji Hasegawa, et al.
  • Journal Title: The Astrophysical Journal Volume: 887 Issue: 2 Pages: 141-141
  • DOI: 10.3847/1538-4357/ab55e4
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Gridded and direct Epoch of Reionisation bispectrum estimates using the Murchison Widefield Array (2019)
  • Author(s): Torotti Cathryn M., Kenji Hasegawa ,et al.
  • Journal Title: Publications of the Astronomical Society of Australia Volume: 36
  • DOI: 10.1017/pasa.2019.15
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Robust statistics towards detection of the 21?cm signal from the Epoch of Reionization (2019)
  • Author(s): Torotti Cathryn M., Kenji Hasegawa, et al.
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 486 Issue: 4 Pages: 5766-5784
  • DOI: 10.1093/mnras/stz1207
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] SILVERRUSH. VII. Subaru/HSC Identifications of Protocluster Candidates at z ? 6?7: Implications for Cosmic Reionization (2019)
  • Author(s): Higuchi Ryo、Ouchi Masami、Ono Yoshiaki、Shibuya Takatoshi、Toshikawa Jun、Harikane Yuichi、Kojima Takashi、Chiang Yi-Kuan、Egami Eiichi、Kashikawa Nobunari、Overzier Roderik、Konno Akira、Inoue Akio K.、Hasegawa Kenji、Fujimoto Seiji、Goto Tomotsugu、Ishikawa Shogo、Ito Kei、Komiyama Yutaka、Tanaka Masayuki
  • Journal Title: The Astrophysical Journal Volume: 879 Issue: 1 Pages: 28-28
  • DOI: 10.3847/1538-4357/ab2192
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Redshift space distortion of 21?cm line at 1 < $z$ < 5 with cosmological hydrodynamic simulations (2019)
  • Author(s): Ando Rika、Nishizawa Atsushi J、Hasegawa Kenji、Shimizu Ikkoh、Nagamine Kentaro
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 484 Issue: 4 Pages: 5389-5399
  • DOI: 10.1093/mnras/stz319
  • Peer Reviewed
• [Journal Article] Detectability of the 21-cm signal during the epoch of reionization with 21-cm Lyman α emitter cross-correlation I (2018)
  • Author(s): Kubota Kenji、Yoshiura Shintaro、Takahashi Keitaro、Hasegawa Kenji、Yajima Hidenobu、Ouchi Masami、Pindor B、Webster R L
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 479 Issue: 2 Pages: 2754-2766
  • DOI: 10.1093/mnras/sty1471
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Detectability of 21 cm-signal during the Epoch of Reionization with 21-cm-Lyman-α emitter cross-correlation II: Foreground contamination (2018)
  • Author(s): Yoshiura S、Line J L B、Kubota K、Hasegawa K、Takahashi K
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 479 Issue: 2 Pages: 2767-2776
  • DOI: 10.1093/mnras/sty1472
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] SILVERRUSH. VI. A simulation of Lyα emitters in the reionization epoch and a comparison with Subaru Hyper Suprime-Cam survey early data (2018)
  • Author(s): Inoue Akio K、Hasegawa Kenji、Ishiyama Tomoaki、Yajima Hidenobu、Shimizu Ikkoh、Umemura Masayuki、Konno Akira、Harikane Yuichi、Shibuya Takatoshi、Ouchi Masami、Shimasaku Kazuhiro、Ono Yoshiaki、Kusakabe Haruka、Higuchi Ryo、Lee Chien-Hsiu
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 70 Issue: 3 Pages: 55-84
  • DOI: 10.1093/pasj/psy048
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Stellar mass dependence of the 21-cm signal around the first star and its impact on the global signal (2018)
  • Author(s): Tanaka Toshiyuki、Hasegawa Kenji、Yajima Hidenobu、Kobayashi Masato I N、Sugiyama Naoshi
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 480 Issue: 2 Pages: 1925-1937
  • DOI: 10.1093/mnras/sty1967
  • Peer Reviewed
• [Journal Article] Thermal Sunyaev-Zel’dovich Effect in the IGM due to Primordial Magnetic Fields (2018)
  • Author(s): Minoda Teppei、Hasegawa Kenji、Tashiro Hiroyuki、Ichiki Kiyotomo、Sugiyama Naoshi
  • Journal Title: Galaxies Volume: 6 Issue: 4 Pages: 143-143
  • DOI: 10.3390/galaxies6040143
  • Peer Reviewed / Open Access
• [Presentation] Development of a novel EoR simulation code and its applications (2019)
  • Author(s): Kenji Hasegawa
  • Organizer: East Asia SKA science workshop
  • Int'l Joint Research / Invited
• [Presentation] GM理論研究のレビュー (2019)
  • Author(s): 長谷川賢二
  • Organizer: Galaxy-IGM workshop 2019
  • Invited
• [Presentation] SKAによるCD/EoRサイエンス (2019)
  • Author(s): 長谷川賢二
  • Organizer: SKA-Japan シンポジウム2019
  • Invited
• [Presentation] East Asia VLBI Networkを用いた宇宙再電離サイエンス (2019)
  • Author(s): 長谷川賢二
  • Organizer: 「銀河進化と遠方宇宙」2019
• [Presentation] 21cm線で探る宇宙初期の構造形成と宇宙再電離 (2018)
  • Author(s): 長谷川賢二
  • Organizer: 初代星初代銀河研究会2018
  • Invited
• [Presentation] 宇宙の夜明けから再電離が起こるまで：これまでの理解と残された課題 (2018)
  • Author(s): 長谷川賢二
  • Organizer: 第31回理論懇シンポジウム「宇宙物理の標準理論：未来へ向けての再考」
  • Invited
• [Presentation] 2020年代の電波観測で期待される宇宙初期サイエンスの進展 (2018)
  • Author(s): 長谷川賢二
  • Organizer: 宇宙電波懇談会シンポジウム2018「電波天文学の将来サイエンス」
  • Invited