2022 Fiscal Year Research-status Report
Understanding formation and properties of gravitational waves events from galactic nuclei
| Project/Area Number |
21K13914
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Trani Alessandro 東京大学, 大学院理学系研究科(理学部), 客員共同研究員 (20881543)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | Gravitational waves / Dynamics / Three-body problem |
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| Outline of Annual Research Achievements |
The first gravitational wave event observed by LIGO-Virgo-Kagra has opened a new observable window on the universe. However, the origin of gravitational wave events is still unknown. We investigated several formation pathways for gravitational wave formation events, which involve few-body interactions and binary stellar evolution processes. In Trani et al. 2022a, we studied how hierarchical triple stars formed in star cluster can produce gravitational wave events from black hole binaries, black hole - neutron stars and black hole - white dwarf binaries. We calculated merger properties and rates, and compared it with the current estimates from LIGO-Virgo-Kagra. In Trani et al. 2022b, we instead proposed a novel way to model the common envelope evolution in binary stars, which is a crucial phase in binary stellar evolution that is necessary to produce gravitational wave events. Further study accomplished in this fiscal year related to the stability of triple systems, which can affect the formation of merging compact binaries. Finally, we have implemented a novel way to model three-body interactions of compact objects in galactic nuclei. We are currently performing a study on: (1) the outcome properties of three-body encounters in galactic nuclei, to better understand how they differ with respect to isolated encounters. This enabled us to analyze the eccentricity of black hole mergers, which may enable us to distinguish from other mergers. (2) The interplay between Kozai-Lidov oscillations and encounters on compact binaries in galactic nuclei.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
I have published more paper than I initially foreseen, due to collaborations and new opportunities related to the subject.
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| Strategy for Future Research Activity |
In the next year, we will finalize the project by completing the analysis and Kozai-Lidov oscillations and three-body encounters in galactic nuclei. In doing so we will produce a catalogue of synthetic merging compact objects to compare with forthcoming observations.
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