Quasinormal-modes of the Kerr-Newman black hole: GW150914 and fundamental physics implications

TL;DR

This paper introduces an analytical waveform model for charged black holes' ringdown signals, enabling constraints on black hole charge and alternative gravity theories from gravitational wave data, exemplified by GW150914.

Contribution

The authors develop a precise analytical ringdown waveform model including overtones for charged black holes, allowing for the first time constraints on black hole charge from gravitational wave observations.

Findings

Black hole charge ratio constrained to $ extless= 0.38$ from GW150914

Scalar-tensor vector gravity deviation parameter limited to $ extless= 0.17$

Model applicable to other black hole mergers with loud ringdown signals

Abstract

We develop an analytical ringdown waveform model, including both the fundamental and the overtone quasinormal modes, for charged black holes and show that it is precise enough to analyze current gravitational wave data. Applying this waveform model to GW150914, the charge to mass ratio of the remnant black hole ($\lambda_f$) has been constrained with the sole ringdown gravitational wave data for the first time and the $90\%$ upper limit is $\lambda_f\leq 0.38$. Correspondingly, the deviation parameter of the scalar-tensor vector gravity ($\alpha_{\rm s}$) is limited to be $\alpha_{\rm s}\leq 0.17$. Our approach can be directly applied to other binary black hole mergers with loud ringdown radiation.