Quasinormal modes of black holes in Weyl gravity: Electromagnetic and gravitational perturbations

TL;DR

This paper investigates the quasinormal modes of black holes in Weyl gravity, analyzing electromagnetic and gravitational perturbations, and compares their spectra to Schwarzschild black holes using analytical and numerical methods.

Contribution

It derives the master equations for perturbations in Weyl gravity and computes the quasinormal mode spectra, highlighting deviations from Schwarzschild black holes due to Weyl gravity effects.

Findings

Weyl black holes have distinct quasinormal spectra from Schwarzschild black holes.

The presence of an additional linear r-term affects the mode frequencies.

Numerical methods confirm the evolution and stability of perturbations.

Abstract

The recent reported gravitational wave detection motivates one to investigate the properties of different black hole models, especially their behavior under (axial) gravitational perturbation. Here, we study the quasinormal modes of black holes in Weyl gravity. We derive the master equation describing the quasinormal radiation by using a relation between the Schwarzschild-anti de Sitter black holes and Weyl solutions, and also the conformal invariance property of the Weyl action. It will be observed that the quasinormal mode spectra of the Weyl solutions deviate from those of the Schwarzschild black hole due to the presence of an additional linear $r$-term in the metric function. We also consider the evolution of the Maxwell field on the background spacetime and obtain the master equation of electromagnetic perturbations. Then, we use the WKB approximation and asymptotic iteration method to calculate the quasinormal frequencies. Finally, the time evolution of modes is studied through the time-domain integration of the master equation.