Quasinormal Modes of Non-Linearly Charged Black Holes surrounded by a Cloud of Strings in Rastall Gravity

TL;DR

This paper investigates the quasinormal modes of non-linearly charged black holes with a string cloud in Rastall gravity, revealing how charge, string clouds, and Rastall parameters influence gravitational wave decay rates.

Contribution

It introduces new black hole solutions in Rastall gravity with non-linear electrodynamics and analyzes their scalar quasinormal modes, highlighting the effects of various parameters.

Findings

Quasinormal modes are affected by non-linear electrodynamic sources at high charge magnitudes.

Gravitational wave decay rates vary with charge, increasing initially then decreasing near q=1 for ABG black holes.

Cloud of strings and Rastall parameters influence the decay rate of gravitational waves.

Abstract

We obtain the black hole solution for the Ay\'on - Beato - Garc\'ia (ABG) type black hole surrounded by a cloud of strings in Rastall gravity and calculate the scalar quasinormal modes of it for a massless scalar field. To have a better visualization of the results, we also introduce a new non-linear electrodynamic source and obtain a black hole solution surrounded by a cloud of strings in the Rastall gravity. We see that the quasinormal modes are affected by the type of non-linear electrodynamic sources in case of higher magnitudes of charge $q$. With increase in the magnitude of charge $q$, gravitational waves decay rapidly for the new black hole solution, while for the ABG black hole, the decay rate increases initially and finally starts to decrease near to $q=1$. We also study the impact of the cloud of strings and other model parameters, including the Rastall parameter on the quasinormal modes for both of the black holes. The gravitational waves decay slowly with increase in the cloud of strings parameter for both of the black holes. Dependency of quasinormal modes on the Rastall parameter is different from a surrounding dark energy field and the decay of gravitational waves may be slow or rapid depending on the value of this parameter.