Binary EMRI Waveform Modeling
Relativistic triple systems and black-hole perturbation theory · arXiv:2410.09796
Binary EMRIs are hierarchical triple systems: a compact binary orbits a supermassive black hole, while the two small bodies also orbit each other. This work builds a relativistic model for that system and asks how the internal binary motion shows up in the gravitational radiation seen far away.
The model combines:
- relativistic three-body dynamics for the motion of the compact binary around the central black hole;
- black-hole perturbation theory for the gravitational radiation;
- a waveform decomposition that separates ordinary EMRI-like motion from signatures of the binary’s internal orbit.
The main conclusion is that a binary EMRI is not just a small correction to a standard single-body EMRI. The internal binary motion produces sideband structure in the radiation and can resonantly excite quasi-normal modes of the central black hole. These features make b-EMRIs a distinct waveform target rather than a minor variant of ordinary EMRIs.
