Quasinormal modes, quasibound states, scalar clouds, and superradiant instabilities of a Kerr-like black hole

TL;DR

This paper investigates how a deformation parameter in a Kerr-like black hole affects scalar field quasinormal modes, quasibound states, superradiant instabilities, and the formation of scalar clouds, using the continued fraction method.

Contribution

It introduces analysis of scalar field eigenfrequencies around a Kerr-like black hole with a new deformation parameter using the continued fraction method.

Findings

Deformation parameter influences quasinormal modes and quasibound states.

Superradiant instability time scales are computed for the modified black hole.

Stationary scalar clouds can form due to superradiant instabilities.

Abstract

We use the continued fraction method to determine the eigenfrequencies associated with a scalar field around a Kerr-like black hole. The Kerr-like metric considered in this article is a subclass of the general parametrization of axisymmetric black holes proposed by Konoplya, Rezzolla and Zhidenko. In addition to its mass $M$ and specific angular momentum $a$, the black hole depends on a third parameter $\eta$, called the deformation parameter. We investigate how the deformation parameter affects the quasinormal modes and the quasibound states of a massive scalar field around the black hole. In particular, we compute the time scales associated with the superradiant instabilities of the scalar field in such a spacetime. The properties of stationary scalar clouds that could be formed by these instabilities are also discussed.