2021 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, ビッグバン宇宙国際研究センター, 研究員 (20881543)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | Gravitationa dynamics |
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| Outline of Annual Research Achievements |
I investigated the role of gravitational three-body interactions in the production of gravitational wave sources. First, I examined three-body encounters in star clusters and how they impact the spin alignment of merging black holes formed from common envelope evolution in binary stars. The proposed scenario matches qualitatively the observed distribution of effective inspiral spin parameter. My work also indicates that the natal black hole spins must be low to be compatible with the observations, supporting the super-efficient angular momentum transport mechanism of stellar interiors via the Tayler-Spruit magnetic dynamo. Second, I investigate merging binary black holes, neutron stars-black holes and white dwarf-black holes in hierarchical triple systems formed dynamically in low-mass star clusters. I compared the properties (eccentricity, masses, merger rate) of compact objects merging via this channel with the current observations, concluding that this scenario might account for outliers in the current observational distribution. Furthermore, I investigate and tested by means of numerical simulations a new statistical theory of the gravitational three-body problem. Finally, I constrained the stability of observed planetary systems from the K2 dataset.
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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 completed the development of a new code to evolve three-body interactions, which has opened new application scenarios.
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| Strategy for Future Research Activity |
I will continue investigating formation scenarios of gravitational wave sources. I will focus on hierarchical triples of PopIII stars. For this, I will implement the a population synthesis code for stellar triples, able to model the effect of stellar evolution on the dynamics of triples. Secondly, I will study the evolution of compact object binaries in the presence of a massive black hole, embedded in a nuclear star cluster.
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| Causes of Carryover |
Equipment for calculations
Travel expenses for conferences and meetings
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