| Project/Area Number |
19K23455
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund |
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| Review Section |
0204:Astronomy, earth and planetary science, and related fields
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Park Hyunbae 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (40842985)
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| Project Period (FY) |
2019-08-30 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | Astrophysics / Cosmology / Reionization / Hydrodynamics / Numerical simulation / Intergalactic medium / Galaxies / Blackholes / Radiative transfer / cosmology / astrophysics / early universe / first stars / numerical simulation / First stars / Gas dynamics / Blackhole |
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| Outline of Research at the Start |
We shall show that the streaming motion between gas and dark matter leads to formation of blackholes of ~100,000 solarmass when universe was 0.1 billion years old. Then, we shall study the signature of those blackholes to be observed by future giant telescopes and gravitational wave experiment.
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| Outline of Final Research Achievements |
During the first billion years of cosmic history, a relative streaming motion between baryon and dark matter impeded gas accretion in dark matter clumps. We explored how this affected the structures of the early universe. We developed a code to accurately generate the initial gas/dark matter density field in the presence of the streaming. Then, we ran numerical simulations to evolve the density fluctuations into structures. We found that the streaming velocity can suppress the formation of small gas structures and reduce the recombination rate, thereby accelerating the ionization of the intergalactic gas by early galaxies. We are also finding that the streaming can cause a sudden collapse of gas into massive blackholes, which can be a progenitor of the supermassive blackhole we find at galactic centers. Lastly, we are investigating whether the streaming can create groups of stars completely devoid of dark matter, just like the globular clusters in today’s galaxies.
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| Academic Significance and Societal Importance of the Research Achievements |
宇宙初期の天体形成は、宇宙進化を理解する上で最重要の課題の一つである。現在の宇宙に存在する銀河やブラックホールといった天体をシミュレーションで再現するには、137億年の宇宙史の間での複雑な効果を取り入れる必要があり、困難を伴う。対して本研究では宇宙開闢から約10億年を対象とするので正確に再現しやすい。ガスと暗黒物質の速度差を考慮した本研究を橋渡しとして、将来的には近傍宇宙の天体の再現が可能となる。
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