Ringing of the regular black hole with asymptotically Minkowski core

TL;DR

This paper investigates the quasi-normal modes of a novel regular black hole with an asymptotically Minkowski core, revealing shorter-lived, higher-energy signals compared to Schwarzschild black holes through analytical and numerical methods.

Contribution

It introduces a new black hole mimicker model and analyzes its quasi-normal modes using WKB approximation and numerical methods, including perturbations of the Regge--Wheeler potential.

Findings

Shorter-lived, higher-energy signals for electromagnetic and scalar perturbations.

Quantitative analysis of mode shifts under potential perturbations.

Comparison with Schwarzschild black hole modes.

Abstract

A Regge--Wheeler analysis is performed for a novel black hole mimicker `the regular black hole with asymptotically Minkowski core', followed by an approximation of the permitted quasi-normal modes for propagating waveforms. A first-order WKB approximation is computed for spin zero and spin one perturbations of the candidate spacetime. Subsequently, numerical results analysing the respective fundamental modes are compiled for various values of the $a$ parameter (which quantifies the distortion from Schwarzschild spacetime), and for various multipole numbers $\ell$. Both electromagnetic spin one fluctuations and scalar spin zero fluctuations on the background spacetime are found to possess shorter-lived, higher-energy signals than their Schwarzschild counterparts for a specific range of interesting values of the $a$ parameter. Analysis as to what happens when one permits perturbations of the Regge--Wheeler potential itself is then conducted, first in full generality, before specialising to Schwarzschild spacetime. A general result is presented explicating the shift in quasi-normal modes under perturbation of the Regge--Wheeler potential.