| 研究実績の概要 |
Extreme mass ratio inspirals, one of the most exciting and promising target sources for space-based interferometers (such as LISA), will offer stringent tests on the general theory of relativity, and provide a wealth of information about the dense environment in galactic centers via the emission of gravitational waves. Our published work in the fiscal year 2021 has demonstrated that tidal resonances induced by the tidal field of a nearby astrophysical object alter the orbital evolution leading to a significant dephasing across observable parameter space. We surveyed how common and vital tidal resonance encounters are over a large part of the relevant orbital parameter space. The results show that EMRI crosses multiple resonances or at least one during an observationally important regime. This result is important as environmental effects can introduce parameter estimation bias, potentially spoiling precision gravitational wave astrophysics. Thus, quantifying and modeling the influence of the environment on inspirals is a crucial problem to work on if we don't want to comprise precision tests. To aid the data analysis challenge, we provided analytic fits for tidal resonant jumps to efficiently study these features in EMRI waveform models. The reverse merit of our work is that if such effects are not present in a detected GW signal, then one can place an upper limit on the surroundings of massive BHs.
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| 今後の研究の推進方策 |
The first essential plan is to relax assumptions and prepare realistic model. In particular, we will generalize the perturber's position and include dynamics. Including the perturber's inclination parameter increase the allowed resonances, and dynamics will significantly improve our understanding of tertiary motion when EMRI crosses multiple resonances during inspiral. As for the data analysis perspective, to analyze the resonant signals, accurate templates that correctly incorporate the effects of the tidal field are required. We employ the Effective Resonance Model and rely on semi-analytic fitting formulae with a simple (yet accurate enough for data analysis purposes) step function approach to inexpensively model resonant jumps.
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