Shielding a charged black hole

TL;DR

This paper introduces a shielding mechanism for charged black holes caused by surrounding charged matter, providing new solutions to Einstein-Maxwell equations and analyzing their effects on photon spheres and quasi-normal modes.

Contribution

It presents the most general electrovacuum solution with a charged black hole in a charged fluid environment and explores the shielding effect within Einstein-Maxwell theory.

Findings

Shielding mechanism is generic and appears in different parametrizations.

Provides the most general electrovacuum solution in a charged environment.

Analyzes the impact on photon sphere, shadow radius, and quasi-normal modes.

Abstract

We describe a shielding mechanism for a charged black hole immersed in a background involving charged matter fields, solely arising from the Einstein-Maxwell field equations. In particular, we consider a charged generalization of the Einstein cluster, that is a charged black hole surrounded by an effective fluid model for a partially charged dust cloud. We show that the shielding mechanism, arising thereof, is generic and appears in a different parametrization of the problem as well. In this process, we provide the most general electrovacuum solution in a spacetime region devoid of charges, but in the presence of a static and spherically symmetric charge distribution elsewhere. Side by side, we also introduce a convenient parametrization, providing the global solution of the Einstein-Maxwell's field equations in the presence of a charged black hole within the environment of charged fluid. We also comment on the nature of the photon sphere, shadow radius and the eikonal quasi-normal modes in the Einstein-Maxwell cluster.