Physical Mechanism of Outflows in Merging Galaxies Revealed with High-spectral-resolution X-ray and high-spatial-resolution Infrared Observations

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K20391
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0204:Astronomy, earth and planetary science, and related fields
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Yamada Satoshi 国立研究開発法人理化学研究所, 開拓研究本部, 基礎科学特別研究員 (90963520)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Keywords: X線天文学 / 赤外線天文学 / 超巨大ブラックホール / 活動銀河核 / 赤外線銀河

Outline of Final Research Achievements

The purpose of our research is to elucidate the outflow physics involved in the formation process of galaxies and central supermassive black holes. In the first year, we developed a multi-wavelength radiation model from X-ray to radio emission. We extracted outflow dust emissions from 84 nearby merging galaxies and succeeded for the first time in systematically showing that outflow dominates as the mergers proceed. We also constructed the largest outflow catalog based on X-ray observations over the past 20 years. In addition, our team developed an X-ray satellite (XRISM) that JAXA led its development, which was successfully launched in September 2023. Innovative data with energy resolution 30 times better than conventional satellites were obtained every day and we are still working on generating results from the initial observation data of the XRISM satellite.

Free Research Field

天文学

Academic Significance and Societal Importance of the Research Achievements

銀河と中心のブラックホールの大きさは10桁も異なるが、両者の質量に強い相関があり、これらを繋ぐ物理が未解明である。その候補であるアウトフローの構造を解明するには、ドップラー効果を受けた輝線や吸収線でその運動を測定することが鍵となる。共同開発したXRISM衛星の打上げの成功により、かつてない精度でアウトフローの運動やエネルギーを測定できる時代が到来した。我々は多波長データモデルの構築、及び、網羅的なX線アウトフロー探査を行い、アウトフロー構造に強い制限を与えた。XRISMの観測も毎日行われ、ブラックホール近傍での物質運動が解明されつつあり、今後は宇宙形成の理解に一層大きな進展を与えられるだろう。