Theoretical Study on Formation of Supermassive Black Holes

2022 Fiscal Year Final Research Report

• Project/Area Number: 17H01102
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Astronomy
• Research Institution: Tohoku University
• Principal Investigator: Omukai Kazuyuki 東北大学, 理学研究科, 教授 (70390622)
• Co-Investigator(Kenkyū-buntansha): 細川 隆史 京都大学, 理学研究科, 准教授 (30413967) ; 大須賀 健 筑波大学, 計算科学研究センター, 教授 (90386508)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: ブラックホール / 星形成 / 銀河形成

Outline of Final Research Achievements

One of the plausible scenarios for the seed formation of supermassive black holes (BHs) is the direct collapse of massive stars. Previously, it was believed that external ultraviolet radiation and primordial gas composition were necessary, but the conditions were too stringent, resulting in a shortage of formed BHs. We conducted numerical simulations of star formation from gas containing trace amounts of heavy elements. When trace amounts of heavy elements were present, stellar clusters formed, and it was found that when the heavy element abundance was less than 1/1000th of the Sun's, the most massive stars became gigantic stars with over 100,000 solar masses, leading to direct collapse and the formation of BH seeds. Based on this new scenario, we perfomed cosmological simulations, demonstrating that it is possible to generate the sufficient seeds of supermassive BHs under the expected threshold metallicity.

Free Research Field

宇宙物理学

Academic Significance and Societal Importance of the Research Achievements

学術的には、巨大ブラックホールの種形成のメカニズムとして、巨大星の直接崩壊がより強固な可能性となったといえる。その具体的な過程が明らかとなったことで、将来の観測的検証や探査における重要な指針となるだろう。また巨大ブラックホールは銀河形成ににおいても重要な役割を果たしており、その形成過程の理解は、銀河の星形成史の解明に寄与する。また巨大ブラックホールは天文学を専門としない人たちにも非常に人気のあるトッピックであり、その起源の解明は社会的にも非常に意義深いといえる。