Comparing second-order gravitational self-force and effective one body waveforms from inspiralling, quasi-circular and nonspinning black hole binaries II: the large-mass-ratio case

TL;DR

This paper compares second-order gravitational self-force waveforms with a GSF-informed effective one body model for large-mass-ratio black hole binaries, demonstrating high accuracy and highlighting the importance of horizon absorption effects.

Contribution

It introduces a GSF-informed EOB waveform model that achieves sub-radian phase agreement with GSF waveforms up to very large mass ratios, including effects like horizon absorption.

Findings

EOB/GSF phase agreement below 1 rad up to end of inspiral for mass ratios up to 500.

High-PN test-mass terms (up to 22PN) are essential for accurate EOB modeling.

Horizon absorption effects become increasingly important at larger mass ratios.

Abstract

We compare recently computed waveforms from second-order gravitational self-force (GSF) theory to those generated by a new, GSF-informed, effective one body (EOB) waveform model for (spin-aligned, eccentric) inspiralling black hole binaries with large mass ratios. We focus on quasi-circular, nonspinning, configurations and perform detailed GSF/EOB waveform phasing comparisons, either in the time domain or via the gauge-invariant dimensionless function $Q_\omega\equiv \omega^2/\dot{\omega}$, where $\omega$ is the gravitational wave frequency. The inclusion of high-PN test-mass terms within the EOB radiation reaction (notably, up to 22PN) is crucial to achieve an EOB/GSF phasing agreement below 1~rad up to the end of the inspiral for mass ratios up to 500. For larger mass ratios, up to $5\times 10^4$, the contribution of horizon absorption becomes more and more important and needs to be accurately modeled. Our results indicate that our GSF-informed EOB waveform model is a promising tool to describe waveforms generated by either intermediate or extreme mass ratio inspirals for future gravitational wave detectors