Axial and polar modes for the ring down of a Schwarzschild black hole with an r dependent mass-function

TL;DR

This paper computes axial and polar quasinormal modes of a Schwarzschild black hole using the AIM, comparing standard GR with an extended model featuring an r-dependent mass-function, and achieves convergence for highly damped modes.

Contribution

It introduces an analytical approach to calculate black hole ringdown modes with an r-dependent mass-function, extending the applicability of the AIM to highly damped modes.

Findings

Achieved convergence for large damping modes using AIM.

Compared standard GR with an extended model with r-dependent mass.

Provided a framework for analyzing other r-dependent mass-functions.

Abstract

The axial and polar modes for the ring down of a Schwarzschild black hole are calculated, by first deriving the Regge-Wheeler and Zerilli equations, respectively, and finally applying the Asymptotic Iteration Method (AIM). We were able to reach up to 500 iterations, obtaining for the first time convergence for a wide range of large damping modes. The General Relativity (GR) and a particular version of an extended model with an r-dependent mass-function are compared. This mass-function allows an analytical solution for the Tortoise coordinate. The example of the mass-function corresponds to the leading correction for extended theories and serves as a starting point to treat other r-dependent parameter mass-functions.