Causal structure of accelerating black holes

TL;DR

This paper analyzes the causal structure of accelerating black holes using null geodesics, constructs Penrose diagrams, and explores new features like singularities and negative mass cases, extending previous knowledge of black hole geometries.

Contribution

It provides a detailed causal analysis of accelerating black holes, including super-accelerating and negative mass cases, with explicit Penrose diagrams and comparisons to Schwarzschild black holes.

Findings

Identification of the causal structure for super-accelerating black holes

Explicit Penrose diagrams for various accelerating black hole cases

Revelation of new singularities and geometries with negative mass

Abstract

Accelerating black holes are described by the so-called C-metric. In this work, we analyse the causal structure of such black holes by using null geodesics. We construct explicitly the relevant Penrose diagrams. First, we recover well-known results associated with the sub-accelerating black holes. Then, we extend the study to the super-accelerating case, in which an additional essential singularity appears. In addition, we consider accelerating black holes with negative masses. We show that they are equivalent to the geometry described by the black hole metric beyond conformal infinity. We compare our results with the Schwarzschild geometry to facilitate understanding and to highlight the interest of the new features.