2021 Fiscal Year Annual Research Report
Evolution of star clusters: from star fromation to gravitational wave emission
| Project/Area Number |
19F19317
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| Research Institution | The University of Tokyo |
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Principal Investigator |
藤井 通子 東京大学, 大学院理学系研究科(理学部), 准教授 (90722330)
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| Co-Investigator(Kenkyū-buntansha) |
WANG LONG 東京大学, 理学(系)研究科(研究院), 外国人特別研究員
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| Project Period (FY) |
2019-11-08 – 2022-03-31
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| Keywords | 星団 / ブラックホール連星 / N体シミュレーション |
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| Outline of Annual Research Achievements |
We have developed a new N-body code, PeTar. Comparing the previous fastest code, the new code has several significant advantages: 1, For more than 100,000 stars, the performance of the code is much faster; 2. Using the slow-down algorithmic regularization method, it can handle 100 % binary fraction; 3. It has a well-designed user interface with rich data analysis tools; 4. It is modularized, and thus, including new functions from other codes.
By including updated stellar evolution code, BSE, we have investigated how the top-heavy IMF affects the event rate of GWs, we found that GCs with a top-heavy IMF is not efficient to produce GW mergers due to a low density after a strong expansion because of massive stellar wind mass loss. We also found the mass ratio distribution of BBHs is also different from that of GCs with the canonical IMF.
We have also carried out the first N-body models of intermediate massive star clusters with up to 100% binary fractions. We found that only massive primordial binaries can affect the long-term evolution of star clusters, but the effect is weak. This suggests that we can ignore low-mass binaries in the numerical modelling of GCs if we only care about the GW events.
By including PeTar in the hydrodynamical code, ASURA+BRIDGE, we studied how the OB binary affect the star formation of Orion nebular star clusters (ONC). We found the ejection of OB stars significantly affect the HII region in star-forming region, and thus, the binary dynamics affect the formation of multiple stellar population in ONC.
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| Research Progress Status |
令和3年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
令和3年度が最終年度であるため、記入しない。
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