Repulsive gravity effects in horizon formation. Horizon remnants in naked singularities

TL;DR

This paper investigates the effects of repulsive gravity in naked singularities, identifying horizon remnants that could help distinguish them from black holes through photon orbit observations.

Contribution

It introduces the concept of horizon remnants in naked singularities and compares their features with black holes, providing new insights into horizon formation and destruction processes.

Findings

Identification of horizon remnants in naked singularities

Differences in photon orbit structures near naked singularities and black holes

Potential observational signatures to distinguish naked singularities from black holes

Abstract

Repulsive gravity is a well known characteristic of naked singularities. In this work, we explore light surfaces and find new effects of repulsive gravity. We compare Kerr naked singularities with the corresponding black hole counterparts and find certain structures that are identified as horizon remnants. We argue that these features might be significant for the comprehension of processes that lead to the formation or eventually destruction of black hole Killing horizons. These features can be detected by observing photon orbits, particularly close to the rotation axis, which can be used to distinguish naked singularities from black hole.