Gravitational Waves from Green's Function Decomposition for a Kerr black hole: I. Equatorial ISCO Plunge

@misc{su2026gravitational,
  title = {{Gravitational Waves from Green's Function Decomposition for a Kerr black hole: I. Equatorial ISCO Plunge}},
  author = {Junquan Su and Neev Khera and Abhishek Chowdhuri and Marc Casals and Huan Yang},
  howpublished = {arXiv},
  year = {2026},
  month = aug,
  doi = {10.48550/arxiv.2608.17943},
  eprint = {2608.17943},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.17943},
}

TY  - UNPB
TI  - Gravitational Waves from Green's Function Decomposition for a Kerr black hole: I. Equatorial ISCO Plunge
AU  - Junquan Su
AU  - Neev Khera
AU  - Abhishek Chowdhuri
AU  - Marc Casals
AU  - Huan Yang
PY  - 2026
DA  - 2026/08/28
PB  - arXiv
DO  - 10.48550/arxiv.2608.17943
UR  - https://arxiv.org/abs/2608.17943
AB  - We present a decomposition of the Kerr Green's function in the time domain, motivated by the frequency-domain split previously studied in the Schwarzschild limit. We show that the identification of a quasinormal-mode contribution, a direct part, and a late-time tail is still available, where the split times are determined by the black hole spin and positions of the emitter and receiver. We have checked this Green's function with time-domain Teukolsky numerical simulations and find excellent agreement. We also apply this decomposed Green's function in the time domain to a model problem with a test particle plunging into a Kerr black hole. The dynamically excited direct wave and quasinormal modes are obtained by convoluting the Green's function with the particle's source term, which may be viewed as the first order in mass ratio of a spinning black hole ringdown.
ER  -