Black-hole scattering with numerical relativity: Self-force extraction and post-Minkowskian validation

TL;DR

This paper uses numerical relativity simulations to analyze black-hole scattering, validating self-force and post-Minkowskian models across various mass ratios and impact parameters, confirming their accuracy in the weak-field regime.

Contribution

It demonstrates that second-order self-force calculations accurately reproduce numerical relativity results for black-hole scattering across all mass ratios.

Findings

Second-order self-force reproduces numerical relativity within error bars.

Good agreement between numerical relativity and post-Minkowskian predictions in weak-field regime.

Higher-order terms are discussed for their importance at larger impact parameters.

Abstract

The asymptotic nature of unbound binary-black-hole encounters provides a clean method for comparing different approaches for modeling the two-body problem in general relativity. In this work, we use numerical relativity simulations of black-hole scattering, generated using the Spectral Einstein Code, to explore the self-force and post-Minkowskian expansions of the scattering angle. First, we use a set of unequal-mass simulations to extract the self-force contributions to the scattering angle. Our main result is that using information up to second-order in the symmetric mass ratio (2SF) reproduces numerical relativity within the error bars across the full range of mass-ratios, including equal mass. Next, we compare our numerical relativity results to state-of-the-art post-Minkowskian predictions at larger impact parameters than previously explored. We find good agreement in the weak-field regime and discuss the relative importance of higher-order terms.