Innovation of the “Interstellar medium” by accurate measurements of the interstellar hydrogen

2019 Fiscal Year Final Research Report

• Project/Area Number: 15H05694
• Research Category: Grant-in-Aid for Specially Promoted Research
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering; Mathematics and Physics
• Research Institution: Nagoya University
• Principal Investigator: FUKUI Yasuo 名古屋大学, 理学研究科, 特任教授 (30135298)
• Co-Investigator(Kenkyū-buntansha): TACHIHARA kengo 名古屋大学, 大学院理学研究科, 准教授 (70432565) ; YAMAMOTO hiroaki 名古屋大学, 大学院理学研究科, 助教 (70444396) ; SANO hidetoshi 名古屋大学, 大学院理学研究科, 特任助教 (50739472) ; OGAWA hideo 大阪府立大学, 理学系研究科, 客員教授 (20022717)
• Research Collaborator: TORII kazufumi ; HAYAKAWA takahiro ; MIZUNO tsunefumi ; TAKEUCHI tsutomu ; TANIGUCHI yoshiaki ; WATANABE naoki ; INOUE tsuyoshi
• Project Period (FY): 2015 – 2019
• Keywords: 星間水素 / 分子雲形成 / 星間ダスト / ガンマ線 / バリオン / NANTEN2

Outline of Final Research Achievements

In order to better understand a role of the interstellar hydrogen and its phase transition, we carried out a comprehensive study of the interstellar hydrogen based on observations and theoretical studies. The observational data were taken with NANTEN2, ALMA, ASKAP, Planck, Fermi, etc. by covering a wide range of wavelength, and the theoretical studies were based on the magneto hydrodynamical simulations of the interstellar hydrogen. Major results of the research are as follows. We revealed that the HI distribution is highly clumpy with dense HI clumps and that the H_2 formation takes place in the clumps at sub-pc scales simultaneously with the CO formation. The CO/H_2 clouds under formation have been identified in Pegasus etc. over a large scale and also with ALMA at very high resolution. In nearby galaxies, we discovered that HI colliding flows trigger the formation of young massive stellar clusters in R136 etc. and opened a new window toward understanding the formation of the ancient globular clusters. We also established the cosmic ray acceleration in the Galactic SNR RXJ1713.7-3946 through a comparison of the new HESS gamma ray data with the hydrogen distribution.

Academic Significance and Societal Importance of the Research Achievements

星間水素は宇宙を構成する最も基本的な物質のひとつであり、その物理的理解は重要である。本研究は、従来にない視点から星間水素の存在形態、物理的化学的性質、ダスト進化、重元素の定量、球状星団の起源、さらに超新星残骸における宇宙線加速の実証という基本問題を、次々に解明して画期的な成果をあげた。その学術的意義は極めて高い。

Free Research Field

天文学