Study on star formation on spiral arms on the Galaxy through unbiased survey of molecular clouds

• Project/Area Number: 18K13580
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 16010:Astronomy-related
• Research Institution: Osaka Prefecture University (2019-2020); Nagoya University (2018)
• Principal Investigator: Nishimura Atsushi 大阪府立大学, 理学(系)研究科(研究院), 非常勤研究員 (50738565)
• Project Period (FY): 2018-04-01 – 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: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
• Keywords: 星形成 / 大質量星 / 分子雲 / 分子雲衝突 / 電波望遠鏡 / 星間物質 / 電波天文学

Outline of Final Research Achievements

This study aims to understand the origin of star formation efficiency in galaxies. Two observation proposals using Nobeyama 45-m radio telescope were accepted, and distributions of molecular gas in the Galaxy are surveyed.In addition, we developed a method to detect cloud-cloud collision event through detailed investigations of gas kinematics. As a result, a number of candidates where the star formation is triggered by the cloud-cloud collision were found regardless of their location in the galactic structures (e.g., arm or spur). This fact indicates that the star formation efficiency in the Galaxy is probably controlled by the frequency of cloud-cloud collision.

Academic Significance and Societal Importance of the Research Achievements

星がどのように生まれるか、は、その後に引き起こされる重元素の生成などを通じて、惑星の起源や生命の誕生に繋がり、宇宙の歴史を紐解く上でも重要な壮大なテーマである。従来、星は、一つの分子雲の中で独立して生まれると素朴に信じられて来た。本研究は、特に大質量星においては、星形成が銀河の中で複数の分子雲が出会い衝突する事を契機に始まる可能性が高い事を観測的に示した。またそれが、銀河内のガス量の大小を問わず、さらには系外銀河においてまで、いかなる場所においても普遍的に同様に起きているであろう事が示された。今後、宇宙における多種多様な星の形成、銀河進化の研究に大きな波及効果を与えると予想される。

Research Products

• [Journal Article] ALMA Observations of Giant Molecular Clouds in M33. I. Resolving Star Formation Activities in the Giant Molecular Filaments Possibly Formed by a Spiral Shock (2020)
  • Author(s): Tokuda K., Muraoka K., Kondo H., Nishimura A., Tosaki T., Zahorecz S., Onodera S., Miura R. E., Torii K., Kuno N., Fujita S., Sano H., Onishi T., Saigo K., Fukui Y., Kawamura A., Tachihara K.
  • Journal Title: The Astrophysical Journal Volume: 896 Issue: 1 Pages: 36-36
  • DOI: 10.3847/1538-4357/ab8ad3
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] ALMA Observations of Giant Molecular Clouds in M33. II. Triggered High-mass Star Formation by Multiple Gas Colliding Events at the NGC 604 Complex (2020)
  • Author(s): Muraoka Kazuyuki、Kondo Hiroshi、Tokuda Kazuki、Nishimura Atsushi、Miura Rie E.、Onodera Sachiko、Kuno Nario、Zahorecz Sarolta、Tsuge Kisetsu、Sano Hidetoshi、Fujita Shinji、Onishi Toshikazu、Saigo Kazuya、Tachihara Kengo、Fukui Yasuo、Kawamura Akiko
  • Journal Title: The Astrophysical Journal Volume: 903 Issue: 2 Pages: 94-94
  • DOI: 10.3847/1538-4357/abb822
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Massive star formation in the Carina nebula complex and Gum 31. I. the Carina nebula complex (2020)
  • Author(s): Fujita Shinji、Sano Hidetoshi、Enokiya Rei、Hayashi Katsuhiro、Kohno Mikito、Tsuge Kisetsu、Tachihara Kengo、Nishimura Atsushi、Ohama Akio、Yamane Yumiko、Ohno Takahiro、Yamada Rin、Fukui Yasuo
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 73 Issue: Supplement_1 Pages: S201-S219
  • DOI: 10.1093/pasj/psaa078
  • Peer Reviewed
• [Journal Article] FOREST unbiased Galactic plane imaging survey with the Nobeyama 45?m telescope (FUGIN). VIII. Possible evidence of cloud?cloud collisions triggering high-mass star formation in the giant molecular cloud M?16 (Eagle Nebula) (2020)
  • Author(s): Nishimura Atsushi、Fujita Shinji、Kohno Mikito、Tsutsumi Daichi、Minamidani Tetsuhiro、Torii Kazufumi、Umemoto Tomofumi、Matsuo Mitsuhiro、Tsuda Yuya、Kuriki Mika、Kuno Nario、Sano Hidetoshi、Yamamoto Hiroaki、Tachihara Kengo、Fukui Yasuo
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 73 Issue: Supplement_1 Pages: S285-S299
  • DOI: 10.1093/pasj/psaa083
  • Peer Reviewed
• [Journal Article] High-mass star formation in Orion B triggered by cloud?cloud collision: Merging molecular clouds in NGC?2024 (2020)
  • Author(s): Enokiya Rei、Ohama Akio、Yamada Rin、Sano Hidetoshi、Fujita Shinji、Hayashi Katsuhiro、Tsutsumi Daichi、Torii Kazufumi、Nishimura Atsushi、Konishi Ryotaro、Yamamoto Hiroaki、Tachihara Kengo、Hasegawa Yutaka、Kimura Kimihiro、Ogawa Hideo、Fukui Yasuo
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 73 Issue: Supplement_1 Pages: S256-S272
  • DOI: 10.1093/pasj/psaa049
  • Peer Reviewed
• [Journal Article] Triggered high-mass star formation in the H?iiregion W?28?A2: A cloud?cloud collision scenario (2020)
  • Author(s): Hayashi Katsuhiro、Yoshiike Satoshi、Enokiya Rei、Fujita Shinji、Yamada Rin、Sano Hidetoshi、Torii Kazufumi、Kohno Mikito、Nishimura Atsushi、Ohama Akio、Yamamoto Hiroaki、Tachihara Kengo、Wong Graeme、Maxted Nigel、Braiding Catherine、Rowell Gavin、Burton Michael、Fukui Yasuo
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 73 Issue: Supplement_1 Pages: S321-S337
  • DOI: 10.1093/pasj/psaa054
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] High-mass star formation in Orion possibly triggered by cloud?cloud collision. III. NGC 2068 and NGC 2071 (2020)
  • Author(s): Fujita Shinji、Tsutsumi Daichi、Ohama Akio、Habe Asao、Sakre Nirmit、Okawa Kazuki、Kohno Mikito、Hattori Yusuke、Nishimura Atsushi、Torii Kazufumi、Sano Hidetoshi、Tachihara Kengo、Kimura Kimihiro、Ogawa Hideo、Fukui Yasuo
  • Journal Title: Publications of the Astronomical Society of Japan Volume: ー Issue: Supplement_1 Pages: S273-S284
  • DOI: 10.1093/pasj/psaa005
  • Peer Reviewed / Open Access
• [Journal Article] FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN). VI. Dense gas and mini-starbursts in the W43 giant molecular cloud complex (2020)
  • Author(s): Kohno, Mikito; Tachihara, Kengo; Torii, Kazufumi; Fujita, Shinji; Nishimura, Atsushi; Kuno, Nario; Umemoto, Tomofumi; Minamidani, Tetsuhiro; Matsuo, Mitsuhiro; Kiridoshi, Ryosuke; Tokuda, Kazuki; Hanaoka, Misaki; Tsuda, Yuya; Kuriki, Mika; Ohama, Akio; Sano, Hidetoshi; Hasegawa, Tetsuo; et al.
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 受理済み
  • Peer Reviewed
• [Journal Article] Nobeyama 45 m Cygnus-X CO Survey. II. Physical Properties of C18O Clumps (2019)
  • Author(s): Takekoshi Tatsuya、Fujita Shinji、Nishimura Atsushi、Taniguchi Kotomi、Yamagishi Mitsuyoshi、Matsuo Mitsuhiro、Ohashi Satoshi、Tokuda Kazuki、Minamidani Tetsuhiro
  • Journal Title: The Astrophysical Journal Volume: 883 Issue: 2 Pages: 156-156
  • DOI: 10.3847/1538-4357/ab3a55
  • Peer Reviewed / Open Access
• [Journal Article] An ALMA View of Molecular Filaments in the Large Magellanic Cloud. I. The Formation of High-mass Stars and Pillars in the N159E-Papillon Nebula Triggered by a Cloud?Cloud Collision (2019)
  • Author(s): Fukui Yasuo、Tokuda Kazuki、Saigo Kazuya、Harada Ryohei、Tachihara Kengo、Tsuge Kisetsu、Inoue Tsuyoshi、Torii Kazufumi、Nishimura Atsushi、Zahorecz Sarolta、Nayak Omnarayani、Meixner Margaret、Minamidani Tetsuhiro、Kawamura Akiko、Mizuno Norikazu、Indebetouw Remy、Sewi?o Marta、Madden Suzanne、Galametz Maud、et al.
  • Journal Title: The Astrophysical Journal Volume: 886 Issue: 1 Pages: 14-14
  • DOI: 10.3847/1538-4357/ab4900
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] An ALMA View of Molecular Filaments in the Large Magellanic Cloud. II. An Early Stage of High-mass Star Formation Embedded at Colliding Clouds in N159W-South (2019)
  • Author(s): Tokuda Kazuki、Fukui Yasuo、Harada Ryohei、Saigo Kazuya、Tachihara Kengo、Tsuge Kisetsu、Inoue Tsuyoshi、Torii Kazufumi、Nishimura Atsushi、Zahorecz Sarolta、Nayak Omnarayani、Meixner Margaret、Minamidani Tetsuhiro、Kawamura Akiko、Mizuno Norikazu、Indebetouw Remy、Sewi?o Marta、Madden Suzanne、Galametz Maud、et al.
  • Journal Title: The Astrophysical Journal Volume: 886 Issue: 1 Pages: 15-15
  • DOI: 10.3847/1538-4357/ab48ff
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45?m telescope (FUGIN). V. Dense gas mass fraction of molecular gas in the Galactic plane (2019)
  • Author(s): Torii Kazufumi、Fujita Shinji、Nishimura Atsushi、Tokuda Kazuki、Kohno Mikito、Tachihara Kengo、Inutsuka Shu-ichiro、Matsuo Mitsuhiro、Kuriki Mika、Tsuda Yuya、Minamidani Tetsuhiro、Umemoto Tomofumi、Kuno Nario、Miyamoto Yusuke
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 印刷中 Issue: Supplement_1
  • DOI: 10.1093/pasj/psz033
  • Peer Reviewed / Open Access
• [Journal Article] Massive star formation in W51 A triggered by cloud-cloud collisions (2019)
  • Author(s): Fujita Shinji、Torii Kazufumi、Kuno Nario,..., Ohama Akio,..., Oasa Yumiko et al.
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 71 Issue: Supplement_1 Pages: 46-46
  • DOI: 10.1093/pasj/psz028
  • Peer Reviewed / Open Access
• [Journal Article] FUGIN: Molecular Gas in Spitzer Bubble N4-Possible Evidence for a Cloud-Cloud Collision as a Trigger of Massive Star Formations (2019)
  • Author(s): Fujita Shinji、Torii Kazufumi、Tachihara Kengo,..., Ohama Akio,..., Oasa Yumiko et al.
  • Journal Title: The Astrophysical Journal Volume: 872 Issue: 1 Pages: 49-63
  • DOI: 10.3847/1538-4357/aafac5
  • Peer Reviewed / Open Access
• [Presentation] ALMA view of 1 pc-scale molecular gas structures in M33 Revealing star-formation activities in molecular filaments/clumps (2019)
  • Author(s): Atsushi NISHIMURA, Kazuyuki MURAOKA, Kazuki TOKUDA, Hiroshi KONDO, Toshikazu ONISHI, Tomoka TOSAKI, Rie MIURA, Kazuki SAIGO, Akiko KAWAMURA, Kazufumi TORII, Sachiko ONODERA, Nario KUNO, Shinji FUJITA, Kengo TACHIHARA, and Yasuo FUKUI
  • Organizer: ALMA2019: Science Results and Cross-Facility Synergies
  • Int'l Joint Research
• [Presentation] Large-scale [CI]/CO survey of the Orion A GMC (2019)
  • Author(s): Atsushi Nishimura (Osaka Prefecture University)
  • Organizer: Sub-mm Spectroscopy and Large Scale Science with ASTE
• [Presentation] 銀河系 Local Spur における分子ガスの密度進化 (2019)
  • Author(s): 西村淳, 上田翔汰, 大西利和 (大阪府立大), 藤田真司, 河野樹人, 堤大陸, 立原研悟, 福井康雄 (名古屋 大), 徳田一起 (大阪府立大/国立天文台), 鳥居和史, 宮本祐介, 南谷哲宏, 西合一矢 (国立天文台), 半田 利弘 (鹿児島大)
  • Organizer: 日本天文学会2019年秋季年会
• [Presentation] Study on formation mechanism of high-mass star forming cores/filaments (2019)
  • Author(s): Atsushi Nishimura (Nagoya Univ.)
  • Organizer: Star formation with ALMA: Evolution from molecular clouds to protostars
• [Presentation] Sagittarius arm における大質量星形成 (2018)
  • Author(s): 西村淳, 大河一貴, 堤大陸, 河野樹人, 藤田真司, 吉池智史, 大浜晶生, 立原研悟, 福井康雄 (名古屋大 学), 南谷哲宏, 鳥居和史 (国立天文台), 大西利和 (大阪府立大学), 久野成夫 (筑波大学)
  • Organizer: 日本天文学会2018年秋季年会
• [Presentation] Cloud collision triggering high-mass star formation in the Sagittarius arm (2018)
  • Author(s): Atsushi Nishimura (Nagoya U), S. Fujita1, M. Kohno1, A. Ohama1, K. Torii2, S. Yoshiike1, D. Tsutsumi1, K. Okawa1, T. Minamidani2, K. Tachihara1, Y. Fukui1 and NANTEN2/FUGIN members (1: Nagoya U, 2: NRO/NAOJ)
  • Organizer: Workshop: Star Formation Triggered by Cloud-Cloud Collision
  • Int'l Joint Research
• [Presentation] Cloud collision triggering high-mass star formation in the Sagittarius arm (2018)
  • Author(s): Atsushi Nishimura (Nagoya U), S. Fujita1, M. Kohno1, A. Ohama1, K. Torii2, S. Yoshiike1, D. Tsutsumi1, K. Okawa1, T. Minamidani2, K. Tachihara1, Y. Fukui1 and NANTEN2/FUGIN members (1: Nagoya U, 2: NRO/NAOJ)
  • Organizer: Shells, clouds and star clusters in galaxies
  • Int'l Joint Research
• [Presentation] FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN): Filament properties and star formation in M17 (2018)
  • Author(s): Atsushi Nishimura (Nagoya University), Tetsuhiro Minamidani, Tomofumi Umemoto, Shinji Fujita, Mitsuhiro Matsuo, Yusuke Hattori, Mikito Kohno, Mitsuyoshi Yamagishi, Yuya Tsuda, Mika Kuriki, Nario Kuno, Kazufumi Torii, Daichi Tsutsumi, Kazuki Okawa, Hidetoshi Sano, Kengo Tachihara, Akio Ohama, and Yasuo Fukui
  • Organizer: Interstellar filament paradigm: On their formation, evolution, and role in star formation
  • Int'l Joint Research
• [Remarks] プレスリリース 2021/3/10 ガス雲衝突から始まる星団誕生の理解が進む
  • URL: http://www.a.phys.nagoya-u.ac.jp/press/20210310/
• [Remarks] Star Formation Triggered by Cloud-Cloud Collision
  • URL: http://a.phys.nagoya-u.ac.jp/workshop/ccc2018/
• [Funded Workshop] Workshop: Star Formation Triggered by Cloud-Cloud Collision (2018)