2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/203192Although the Kerr solution is common to many gravity theories, its perturbations are different in different theories. Hence, perturbed Kerr black holes can probe deviations from General Relativity.minor changes to match version published in Phys. Rev. LettGeneral Relativity and Quantum CosmologyAstrophysicstext