Quasi-Black Holes from Extremal Charged Dust

TL;DR

This paper constructs and analyzes quasi-black hole solutions from extremal charged dust, which are nearly indistinguishable from true black holes but remain nonsingular, providing insights into horizon formation and gravitational properties.

Contribution

It introduces a method to generate quasi-black hole solutions using extremal charged dust within the Majumdar-Papapetrou formalism, comparing their properties with magnetic monopole-based solutions.

Findings

Solutions can be constructed with or without hair.

They are arbitrarily close to having a horizon but remain nonsingular.

Exterior observers find it difficult to distinguish these from true black holes.

Abstract

One can construct families of static solutions that can be viewed as interpolating between nonsingular spacetimes and those containing black holes. Although everywhere nonsingular, these solutions come arbitrarily close to having a horizon. To an observer in the exterior region, it becomes increasingly difficulty to distinguish these from a true black hole as the critical limiting solution is approached. In this paper we use the Majumdar-Papapetrou formalism to construct such quasi-black hole solutions from extremal charged dust. We study the gravitational properties of these solutions, comparing them with the the quasi-black hole solutions based on magnetic monopoles. As in the latter case, we find that solutions can be constructed with or without hair.