Understanding formation and properties of gravitational waves events from galactic nuclei
| Project/Area Number |
21K13914
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics
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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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| Project Status |
Granted (Fiscal Year 2022)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2023: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2022: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2021: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Keywords | Gravitational waves / Dynamics / Three-body problem / Gravitationa dynamics / Black hole physics / Galactic nuclei / Stellar dynamics |
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| Outline of Research at the Start |
This project aims at characterizing the properties of gravitational waves (GWs) originating from compact object binaries residing in galactic nuclei. The astrophysical origin of gravitational wave sources is still unknown. Nuclear star clusters around a central massive black hole (BH) are expected to be abundant in stellar BH remnants and BH binaries. In this project I will develop an innovative hybrid Monte-Carlo/N-body model able to follow the evolution of binaries in galactic nuclei in order to provide a complete understanding of the evolution of GW progenitors in galactic nuclei.
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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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Report
(2 results)
Research Products
(22 results)
