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arXiv · 2405.10270

Quadratic quasi-normal mode dependence on linear mode parity

Patrick Bourg·Rodrigo Panosso Macedo·Andrew Spiers·Benjamin Leather·Béatrice Bonga·Adam Pound
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Abstract

Quasinormal modes (QNMs) uniquely describe the dominant piece of the gravitational-wave ringdown of postmerger black holes. While the linear QNM regime has been extensively studied, recent work has highlighted the importance of second-perturbative-order, quadratic QNMs (QQNMs) arising from the nonlinear coupling of linear QNMs. Previous attempts to quantify the magnitude of these QQNMs have shown discrepant results. Using a new hyperboloidal framework, we resolve the discrepancy by showing that the QQNM/QNM ratio is a function not only of the black hole parameters but also of the ratio between even- and odd-parity linear QNMs: the ratio QQNM/QNM depends on what created the ringing black hole, but only through this ratio of even- to odd-parity linear perturbations.

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Patrick Bourg, Rodrigo Panosso Macedo, Andrew Spiers, Benjamin Leather, Béatrice Bonga, Adam Pound. 2024-05-16. Quadratic quasi-normal mode dependence on linear mode parity. https://arxiv.org/abs/2405.10270

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