Revisiting non-linearity in binary black hole mergers

TL;DR

This paper investigates the non-linear dynamics of binary black hole mergers by visualizing non-linearity in the strong-field region, challenging the assumption that non-linear effects are negligible at infinity.

Contribution

It provides a novel visualization of non-linear effects in the strong-field region during black hole mergers, addressing where non-linearities dissipate.

Findings

Non-linearities are concentrated in the strong-field region.

Linear models with overtones accurately describe the post-merger waveform.

Non-linear effects do not significantly propagate to infinity.

Abstract

Recently, it has been shown that with the inclusion of overtones, the post-merger gravitational waveform at infinity of a binary black hole system is well-modelled using pure linear theory. However, given that a binary black hole merger is expected to be highly non-linear, where do these non-linearities, which do not make it out to infinity, go? We visualize quantities measuring non-linearity in the strong-field region of a numerical relativity binary black hole merger in order to begin to answer this question.