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arXiv · 2107.14195

Overtones, mirror modes, and mode-mixing in binary black hole mergers

Arnab Dhani·B. S. Sathyaprakash
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Abstract

Gravitational waves emitted in the aftermath of a black hole binary coalescence have characteristic complex frequencies called quasinormal modes (QNMs). These can be used to test the nature of the merger remnant, e.g. a test of the black hole "no-hair" theorem. The relative excitation amplitudes of the QNMs contain information about the progenitor system and can be employed to test the consistency between the pre- and post-merger signals. The post-merger signal from numerical relativity (NR) simulations of binary black holes exhibit a rich structure that has to be understood to fully exploit the information contained therein. In this study, we examine the importance of \emph{overtones} and \emph{mirror} modes for a set of mass ratios of non-spinning black hole binaries and a host of multipole modes corresponding to spherical harmonic indices $l\leq4$ and $m\leq3.$ We find that the first overtone is most important in the leading mode for a given $m$ and decreases for sub-dominant modes. The contribution of the fundamental mirror mode is most significant for $m=1$ and increases with mass ratio, although the model systematics are not affected significantly by mirror modes. Mode-mixing is the dominant effect for the sub-leading modes of a given $m$ and minimally affects the leading mode.

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Arnab Dhani, B. S. Sathyaprakash. 2021-07-29. Overtones, mirror modes, and mode-mixing in binary black hole mergers. https://arxiv.org/abs/2107.14195

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