Quasar absorption systems as a probe of the galaxy and the circum galactic medium

• Project/Area Number: 16K05299
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Astronomy
• Research Institution: Tokyo University of Science
• Principal Investigator: Okoshi Katsuya 東京理科大学, 基礎工学部教養(長万部), 准教授 (50453832)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: クエーサー吸収線系 / 銀河形成 / 銀河間物質 / 理論物理学 / 理論天文学

Outline of Final Research Achievements

We have investigated an evolutionary relation between galaxy and the circum-galactic medium (CGM) through quasar absorption systems, Damped Lyman-alpha (DLA) absorption systems, which exhibit the highest HI column densities in the universe, and metal absorption systems. Our main results are as follows:
(1) At redshift z=1-2, the quasar absorption systems in the CGM show a strong correlation between the HI column densities and the low-ion column densities (e.g., MgII) with a scale within about 10 kpc. The multiple absorption systems indicate that the CGM extends up to a scale of about 500 kpc which is larger than the halo size of typical galaxy. (2) Our surveys for DLA galaxies on the Subaru/Keck observations put constraint on an upper limit of the star formation rates of 1 0 M(solar)/yr.
Further investigation based on statistically significant sample size is required by carrying out both radio and optical/infrared surveys for DLA galaxies.

Academic Significance and Societal Importance of the Research Achievements

天文学では、我々の住む銀河系が、いつ誕生し、どのように進化をして現在の姿になっているかを解明することが重要な問いである。宇宙には、銀河系と似た銀河が数多く存在し、現代の大型望遠鏡によって、宇宙初期に遡って銀河の進化過程を詳細に観測できるようになった。本研究では、すばる望遠鏡などの大型望遠鏡を駆使して、原始銀河の周辺域ガスの物理的・化学的特性を調べることにより、銀河がどのように進化してきたのかという問いに対して有益な示唆を与えることができた。

Research Products

• [Journal Article] Quantifying the Effect of Field Variance on the Hα Luminosity Function with the New Numerical Galaxy Catalog (ν 2GC) (2020)
  • Author(s): Ogura Kazuyuki、Nagashima Masahiro、Shimakawa Rhythm、Hayashi Masao、Kobayashi Masakazu A. R.、Oogi Taira、Ishiyama Tomoaki、Koyama Yusei、Makiya Ryu、Okoshi Katsuya、Onodera Masato、Shirakata Hikari
  • Journal Title: The Astrophysical Journal Volume: 895 Issue: 1 Pages: 9-9
  • DOI: 10.3847/1538-4357/ab8631
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Multiple Absorption Systems in the Lines of Sight to Quadruply Lensed Quasar H1413+1143 As a Probe of the Circumgalactic medium around Dwarf Galaxy (2019)
  • Author(s): Okoshi Katsuya、Minowa Yosuke、Kashikawa Nobunari、Koyamada Suzuka、Misawa Toru
  • Journal Title: Proceedings of the International Astronomical Union Volume: 14 Issue: S344 Pages: 305-308
  • DOI: 10.1017/s1743921318006683
  • Open Access
• [Journal Article] Evolution of dwarf galaxies in a semi-analytic galaxy formation model (2019)
  • Author(s): Nagashima Masahiro、Enoki Motohiro、Ishiyama Tomoaki、Kobayashi Masakazu A. R.、Makiya Ryu、Ogura Kazuyuki、Okamoto Takashi、Okoshi Katsuya、Oogi Taira、Shirakata Hikari
  • Journal Title: Proceedings of the International Astronomical Union Volume: 14 Issue: S344 Pages: 491-494
  • DOI: 10.1017/s1743921318005471
  • Open Access
• [Journal Article] Current Status of QAL (1) - Quasar Absorption Line System - (2019)
  • Author(s): Okoshi Katsuya & Ogura Kazuyuki
  • Journal Title: Cosmic Shadow 2018 ~クエーサー吸収線系でみる宇宙~ Volume: 1 Pages: 1-6
• [Journal Article] Current Status of QALs (2)---Star-forming galaxies, environments and DLAs (2019)
  • Author(s): Ogura Kazuyuki & Ogura Kazuyuki
  • Journal Title: Cosmic Shadow 2018 ~クエーサー吸収線系でみる宇宙~ Volume: 1 Pages: 7-10
• [Journal Article] The New Numerical Galaxy Catalogue (ν2GC): properties of active galactic nuclei and their host galaxies (2019)
  • Author(s): Shirakata, H., Okamoto, T., Kawaguchi, T., Nagashima, M., Ishiyama, T., Makiya, R., Kobayashi, M. A. R., Enoki, M., Oogi, T., Okoshi, K.
  • Journal Title: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Volume: 482 Issue: 4 Pages: 48464873-48464873
  • DOI: 10.1093/mnras/sty2958
  • Peer Reviewed / Open Access
• [Journal Article] Resolving the Internal Structure of Circumgalactic Medium Using Gravitationally Lensed Quasars (2017)
  • Author(s): Koyamada, S., Misawa, T., Inada, N., Oguri, M., Kashikawa, N. & Okoshi, K.
  • Journal Title: The Astrophysical Journal Volume: 851 Issue: 2 Pages: 88100-88100
  • DOI: 10.3847/1538-4357/aa9a3a
  • Peer Reviewed
• [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
• [Presentation] Absorption Systems in Lines of Sight toward Cloverleaf (2020)
  • Author(s): Okoshi, K
  • Organizer: The blind search for hidden galaxies in an abundant line of sight
  • Int'l Joint Research / Invited
• [Presentation] Semi-analytic model of emission-line galaxies (2020)
  • Author(s): Ogura, K., Nagashima, M., Shimakawa, R., Hayashi, M., Oogi, T., Kobayashi, M., Ishiyama, T., Koyama, Y., Makiya, R., Okoshi, K., Onodera, M., and Shirakata, H.
  • Organizer: HSC-AGN face-to-face meeting #11
  • Int'l Joint Research
• [Presentation] Semi-analytic examination for the cosmic variance on the Hα emitter (2019)
  • Author(s): Ogura, K., Nagashima, M., Shimakawa, R., Hayashi, M., Oogi, T., Kobayashi, M., Ishiyama, T., Koyama, Y., Makiya, R., Okoshi, K., Onodera, M., and Shirakata, H.
  • Organizer: Subaru Telescope 20th anniversary, Optical & Infrared Astronomy for the Next Decade
  • Int'l Joint Research
• [Presentation] ν2GCによる輝線銀河モデル (2019)
  • Author(s): 小倉和幸, 長島雅裕, 嶋川里澄, 林将央, 小林正和, 大木平, 石山智明, 小山佑世, 真喜屋龍, 大越克也, 小野寺仁人, 白方光
  • Organizer: SWANS理論班会議
• [Presentation] The cosmic variance on the Hα luminosity function examined by the new numerical galaxy catalog (ν2GC) (2019)
  • Author(s): 小倉和幸, 長島雅裕, 嶋川里澄, 林将央, 小林正和, 大木平, 石山智明, 小山佑世, 真喜屋龍, 大越克也, 小野寺仁人, 白方光
  • Organizer: 日本天文学会2019年秋季年会
• [Presentation] 準解析的銀河形成モデルν2GCによる輝線銀河モデルから見る広視野分光探査の重要性 (2019)
  • Author(s): 小倉和幸, 長島雅裕, 嶋川里澄, 林将央, 小林正和, 大木平, 石山智明, 小山佑世, 真喜屋龍, 大越克也, 小野寺仁人, 白方光
  • Organizer: 第１回科学研究部シンポジウム 銀河赤方偏移探査による宇宙論研究会
• [Presentation] Multiple Absorption Systems in the Lines of Sight to Quadruply Lensed Quasar H1413+1143 As a Probe of the Circumgalactic medium around Dwarf Galaxy (2018)
  • Author(s): Okoshi, K., Minowa, Y., Kashikawa, N., Koyamada, S., and Misawa, T.
  • Organizer: International Astronomical Union, Symposium 344 `Dwarf Galaxies: From the Deep Universe to the Present'
  • Int'l Joint Research
• [Presentation] Nagashima, M., Enoki, M., Ishiyama, T., Kobayashi, M.A.R, Makiya, R., Ogura, K., Okamoto, T., Okoshi, K., Oogi, T., and Shirakata, H. (2018)
  • Author(s): Evolution of dwarf galaxies in a semi-analytic galaxy formation model
  • Organizer: International Astronomical Union, Symposium 344 `Dwarf Galaxies: From the Deep Universe to the Present'
  • Int'l Joint Research
• [Presentation] Quasar Absorption Line Systems - Current Status of QALs - (2018)
  • Author(s): Okoshi, K., & Ogura, K.
  • Organizer: Cosmic Shadow 2018
  • Invited
• [Presentation] Star-forming galaxies, environments and DLAs (2018)
  • Author(s): Ogura, K., & Okoshi, K.
  • Organizer: Cosmic Shadow 2018
  • Invited
• [Presentation] レンズクエーサーを用いた多視線分光観測によるCGMの内部構造の調査 (2017)
  • Author(s): 小山田涼香、三澤透、稲田直久、大栗真宗、柏川伸成、大越克也
  • Organizer: 日本天文学会2017年秋季年会
• [Presentation] 多視線分光観測によるCGM吸収体の空間分布調査 (2017)
  • Author(s): 小山田涼香、三澤透、稲田直久、大栗真宗、柏川伸成、大越克也
  • Organizer: CHORUS+Galaxy+IGM Workshop 2017
• [Presentation] QSO Absorption System -- DLA & IGM (2016)
  • Author(s): Okoshi, K.
  • Organizer: Galaxy-IGM 研究会
  • Place of Presentation: 信州大学
  • Year and Date: 2016-12-05
  • Invited
• [Presentation] Resolving Internal Structure of Circum-Galactic Medium Using Gravitationally Lensed Quasars (2016)
  • Author(s): Koyamada, S., Inada, N., Oguri, M., Okoshi, K., & Kashikawa, N.
  • Organizer: Galaxy-IGM 研究会
  • Place of Presentation: 信州大学
  • Year and Date: 2016-12-05