A boosted Kerr black hole solution and the structure of a general astrophysical black hole

TL;DR

This paper derives a new exact solution to Einstein's equations describing a boosted Kerr black hole with three parameters, revealing asymmetries in the ergosphere while core structures remain unchanged, impacting astrophysical processes.

Contribution

It introduces the most general astrophysical black hole model including boost effects, extending the Kerr solution to account for motion relative to an asymptotic frame.

Findings

The ergosphere becomes asymmetric due to boost.

Core black hole structures are unaffected by boost.

Potential implications for Penrose processes in asymmetric ergospheres.

Abstract

A solution of Einstein's vacuum field equations that describes a boosted Kerr black hole relative to an asymptotic Lorentz frame at the future null infinity is derived. The solution has three parameters (mass, rotation and boost) and corresponds to the most general configuration that an astrophysical black hole must have; it reduces to the Kerr solution when the boost parameter is zero. In this solution the ergosphere is north-south asymmetric, with dominant lobes in the direction opposite to the boost. However the event horizon, the Cauchy horizon and the ring singularity, which are the core of the black hole structure, do not alter, being independent of the boost parameter. Possible consequences for astrophysical processes connected with Penrose processes in the asymmetric ergosphere are discussed.