Extreme Mass-Ratio Inspirals in the Effective-One-Body Approach: Quasi-Circular, Equatorial Orbits around a Spinning Black Hole

TL;DR

This paper develops and validates an effective-one-body waveform model for extreme-mass ratio inspirals around spinning black holes, achieving high accuracy and computational efficiency suitable for LISA data analysis.

Contribution

The paper introduces a calibrated EOB model for EMRIs with high accuracy, validated against Teukolsky-based waveforms, and assesses the impact of higher-order terms on phase evolution.

Findings

Phase agreement better than 1 radian over 2-6 months.

Match quality exceeds 97% over 4-9 months.

Higher-order mass ratio terms cause up to 30 radians phase correction in one year.

Abstract

We construct effective-one-body waveform models suitable for data analysis with LISA for extreme-mass ratio inspirals in quasi-circular, equatorial orbits about a spinning supermassive black hole. The accuracy of our model is established through comparisons against frequency-domain, Teukolsky-based waveforms in the radiative approximation. The calibration of eight high-order post-Newtonian parameters in the energy flux suffices to obtain a phase and fractional amplitude agreement of better than 1 radian and 1 % respectively over a period between 2 and 6 months depending on the system considered. This agreement translates into matches higher than 97 % over a period between 4 and 9 months, depending on the system. Better agreements can be obtained if a larger number of calibration parameters are included. Higher-order mass ratio terms in the effective-one-body Hamiltonian and radiation-reaction introduce phase corrections of at most 30 radians in a one year evolution. These corrections are usually one order of magnitude larger than those introduced by the spin of the small object in a one year evolution. These results suggest that the effective-one-body approach for extreme mass ratio inspirals is a good compromise between accuracy and computational price for LISA data analysis purposes.