Quasinormal modes of test fields around regular black holes

TL;DR

This paper investigates the stability and quasinormal modes of scalar, electromagnetic, and gravitational fields around regular black holes, revealing how their frequencies and wave scattering properties depend on black hole parameters.

Contribution

It provides the first detailed analysis of QNM frequencies and greybody factors for test fields in Hayward, Bardeen, and Ayón-Beato-García regular black hole spacetimes using sixth order WKB approximation.

Findings

Test fields are stable in all studied regular black hole spacetimes.

Damping of QNMs is less in regular black holes compared to Schwarzschild.

Increasing black hole charge enhances wave reflection and reduces transmission.

Abstract

We study scalar, electromagnetic and gravitational test fields in the Hayward, Bardeen and Ay\'on-Beato-Garc\'ia regular black hole spacetimes and demonstrate that the test fields are stable in all these spacetimes. Using the sixth order WKB approximation of the linear "axial" perturbative scheme, we determine dependence of the quasinormal mode (QNM) frequencies on the characteristic parameters of the test fields and the spacetime charge parameters of the regular black holes. We give also the greybody factors, namely the transmission and reflection coefficients of scattered scalar, electromagnetic and gravitational waves. We show that damping of the QNMs in regular black hole spacetimes is suppressed in comparison to the case of Schwarzschild black holes, and increasing charge parameter of the regular black holes increases reflection and decreases transmission factor of incident waves for each of the test fields.