Quasinormal modes and late-time tails in the background of Schwarzschild black hole pierced by a cosmic string: scalar, electromagnetic and gravitational perturbations

TL;DR

This paper investigates how a cosmic string piercing a Schwarzschild black hole influences quasinormal modes and late-time tail behaviors across scalar, electromagnetic, and gravitational perturbations, revealing signatures of the string despite the local metric similarity.

Contribution

It demonstrates that quasinormal modes and late-time tails can encode physical signatures of a cosmic string in a Schwarzschild black hole background, especially through gravitational perturbations.

Findings

Quasinormal modes and tails reflect the presence of the cosmic string.

Gravitational perturbations decay slower than scalar and electromagnetic ones.

The cosmic string's effect can be detected via these perturbation signatures.

Abstract

We have studied the quasinormal modes and the late-time tail behaviors of scalar, electromagnetic and gravitational perturbations in the Schwarzschild black hole pierced by a cosmic string. Although the metric is locally identical to that of the Schwarzschild black hole so that the presence of the string will not imprint in the motion of test particles, we found that quasinormal modes and the late-time tails can reflect physical signatures of the cosmic string. Compared with the scalar and electromagnetic fields, the gravitational perturbation decays slower, which could be more interesting to disclose the string effect in this background.