Hair imprints of the gravitational decoupling and hairy black hole spectroscopy

TL;DR

This paper investigates the gravitational wave signatures of hairy black holes formed via gravitational decoupling, computing quasinormal modes to identify unique physical signatures distinguishing them from standard black holes.

Contribution

It introduces a method to analyze gravitational waveforms of hairy black holes using perturbation theory and higher-order WKB, highlighting distinctive signatures of primary hair.

Findings

Quasinormal modes differ from Reissner-Nordström black holes.

Hair imprint affects gravitational wave ringdown signals.

Distinct signatures can help identify hairy black holes observationally.

Abstract

Hairy black holes by gravitational decoupling (GD) are probed to derive the gravitational waveform produced by perturbation theory applied to these compact objects. Using the Regge-Wheeler and Zerilli equations governing the metric perturbations and applying a higher-order WKB method, the quasinormal modes (QNMs) are computed and discussed. Compared to the QNMs produced in the ringdown phase of Reissner-Nordstr\"om black hole solutions, it yields a clear physical signature of primary hair imprinting the hairy GD black hole gravitational waveforms.