Maxwell Fields in Boosted Kerr Black Holes

TL;DR

This paper investigates electromagnetic fields around boosted Kerr black holes, analyzing their emission patterns and potential astrophysical phenomena like jets, using Kerr-Schild coordinates and considering relativistic boosts.

Contribution

It introduces a method to analyze electromagnetic configurations in boosted Kerr black holes using Kerr-Schild coordinates and extends the analysis to relativistic boosts in Bondi-Sachs spacetime.

Findings

Identified nonsingular electromagnetic emission patterns for boosted Kerr black holes.

Analyzed the impact of boost parameter variations on electromagnetic emissions.

Discussed mechanisms resembling magnetospheres and jet formation in boosted black holes.

Abstract

The spacetime of a boosted Bondi-Sachs rotating black hole is considered as a proper background to examine electromagnetic configurations connected to analytic solutions of Maxwell equations. In our analysis, we first use the Bondi-Sachs transformations in order to bring the boosted rotating black hole metric into the Kerr-Schild form, from which zero angular momentum observers (ZAMOs) are constructed via the ADM formalism. In Kerr-Schild coordinates we obtain the Killing fields as sources of Maxwell electrodynamics, and we fix a ZAMO in order to evaluate the components of the electric and magnetic fields, from which we obtain nonsingular patterns of an eventual momentum-energy emission of a boosted Kerr-Schild black hole. Distinct patterns are examined and discussed in the case of variations of the boost parameter $\gamma$. We extend our analysis by considering the nonsingular electromagnetic emission in the framework of a boosted Bondi-Sachs rotating black hole, as it moves at relativistic speeds. We also discuss possible mechanisms that may resemble magnetospheres of rotating boosted black holes and give rise to hydromagnetic flows from accretion discs and to the production of jets.