Axial gravitational perturbations and echo-like signals of a hairy black hole from gravitational decoupling

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Yang, Yi, Ovgun, Ali, Lambiase, Gaetano, Liu, Dong, Long, Zheng-Wen
Format: Preprint
Publié: 2026
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866917391141699584
author Yang, Yi
Ovgun, Ali
Lambiase, Gaetano
Liu, Dong
Long, Zheng-Wen
author_facet Yang, Yi
Ovgun, Ali
Lambiase, Gaetano
Liu, Dong
Long, Zheng-Wen
contents We study axial gravitational perturbations of a hairy black hole constructed in the framework of gravitational decoupling and investigate the geometric origin of echo-like late-time signals in this spacetime. We derive the odd-parity master equation and the corresponding effective potential, and we compute the quasinormal-mode spectrum by using frequency-domain and time-domain methods. We show that, in a suitable region of parameter space, the axial potential develops a double-peak structure that supports a trapping cavity and gives rise to echo-like late-time waveforms. Rather than imposing near-horizon reflectivity by hand, the delayed pulses therefore arise dynamically from the geometry of the effective potential. We also clarify that the parameter region exhibiting echoes need not coincide with the region in which the weak energy condition is satisfied everywhere outside the event horizon, and this distinction must be taken into account when interpreting the physical status of the solution. Our results provide a useful framework for probing black-hole hair through gravitational-wave ringdown and for exploring possible observational departures from the standard no-hair paradigm.
format Preprint
id arxiv_https___arxiv_org_abs_2604_02164
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Axial gravitational perturbations and echo-like signals of a hairy black hole from gravitational decoupling
Yang, Yi
Ovgun, Ali
Lambiase, Gaetano
Liu, Dong
Long, Zheng-Wen
General Relativity and Quantum Cosmology
We study axial gravitational perturbations of a hairy black hole constructed in the framework of gravitational decoupling and investigate the geometric origin of echo-like late-time signals in this spacetime. We derive the odd-parity master equation and the corresponding effective potential, and we compute the quasinormal-mode spectrum by using frequency-domain and time-domain methods. We show that, in a suitable region of parameter space, the axial potential develops a double-peak structure that supports a trapping cavity and gives rise to echo-like late-time waveforms. Rather than imposing near-horizon reflectivity by hand, the delayed pulses therefore arise dynamically from the geometry of the effective potential. We also clarify that the parameter region exhibiting echoes need not coincide with the region in which the weak energy condition is satisfied everywhere outside the event horizon, and this distinction must be taken into account when interpreting the physical status of the solution. Our results provide a useful framework for probing black-hole hair through gravitational-wave ringdown and for exploring possible observational departures from the standard no-hair paradigm.
title Axial gravitational perturbations and echo-like signals of a hairy black hole from gravitational decoupling
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2604.02164