Signatures of regular black holes from the shadow of Sgr A* and M87*

TL;DR

This study explores whether regular black holes with a Minkowski core can explain the observed shadows of Sgr A* and M87*, suggesting they favor a small non-zero charge and providing insights into horizon-scale gravitational physics.

Contribution

It demonstrates that regular black holes with a Minkowski core are consistent with observed black hole shadows, offering a potential alternative to classical singular black holes.

Findings

Shadows of M87* and Sgr A* favor regular black holes with small non-zero charge.

Computed shadow observables align with observations for regular black holes.

Implications for horizon-scale gravity and black hole models are discussed.

Abstract

With the recent release of the black hole image of Sgr A* alongside the earlier image of M87*, one can now really hope to acquire a better understanding of the gravitational physics at the horizon scale. In this paper, we investigate the prospect of the regular black hole scenario with a Minkowski core in explaining the observed shadow of M87* and Sgr A*. Regular black holes generally appear in Einstein gravity coupled to non-linear electrodynamics and are interesting as they can evade the r = 0 curvature singularity arising in general relativity. Using the previously determined mass and distance we compute the observables associated with the black hole shadow. These when compared with the observed angular diameter reveal that the shadow of M87* and Sgr A* favor the regular black hole scenario with a small but non-zero charge. The implications are discussed.