2021 Fiscal Year Annual Research Report
Can Baryon-Dark Matter Streaming Motion Explain Supermassive Blackholes in the Early Universe?
| Project/Area Number |
19K23455
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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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| Keywords | Cosmology / Reionization / Galaxies / Blackholes / Hydrodynamics / Radiative transfer |
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| Outline of Annual Research Achievements |
I have developed a code that generates the density/velocity field of the early universe, where we start the simulation of structure formation in the presence of the baryon-dark matter streaming velocity. Then, we tested how the (in)accurate initial conditions can impact the amount of gas accreted in the galaxies and the amount that is turned into stars when the universe was about 100 millions year old. [2] With our code, we showed that the streaming velocity decreases the number of gas structures when the universe is about one billion years old, which affects the ionization pattern of the universe produced by early galaxies. This ionization pattern will be soon observed by upcoming radio surveys. [3] We have run a series of blackhole-formation simulations with different levels of streaming velocity to explore if the streaming velocity can promote the formation of massive blackholes in the early universe. [4] As a side project, I studied how much the neutral gas medium in the intergalactic space can scatter the Lyman alpha emission off the line of sight and affect the observed line strength from early galaxies. [5] As another side project, I the subsequent journey of the scattered Lyman alpha light until it arrives us today. I showed this light would be observed as a diffuse halo of light around the source galaxy, and we will be able to reconstruct the intrinsic emission from the galaxy before being processed in the intergalactic space.
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