Parametrized quasinormal modes, greybody factors and their correspondence

We present a detailed study of quasinormal modes and greybody factors in the context of the parametrized quasinormal mode framework, in which modifications to general relativity are introduced as small corrections in the potential. We deduce the QNMs’ and GBFs’ dependence on the order of the modifications and their polynomial power. We also test the validity of the recently proposed QNM-GBF correspondence in the pQNM framework by inspecting the regime at which it breaks down.