Hair imprints of the gravitational decoupling and hairy black hole spectroscopy

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.