Ergosphere, photon region structure, and the shadow of a rotating charged Weyl black hole

TL;DR

This paper investigates the photon region and shadow of a rotating charged Weyl black hole, revealing how charge and spin influence its observable shadow and providing insights into the black hole's ergosphere and potential charge source.

Contribution

It provides a detailed analysis of the photon region, shadow structure, and ergosphere of a rotating charged Weyl black hole, including comparisons with M87* and implications for its electric charge.

Findings

Shadow shape varies from oblate to sharp with increasing spin

Estimated electric charge of M87* could be about 10^36 protons

Derived the ergosphere and static limit for the black hole

Abstract

In this paper, we explore the photon region and the shadow of the rotating counterpart of a static charged Weyl black hole, which has been previously discussed according to null and time-like geodesics. The rotating black hole shows strong sensitivity to the electric charge and the spin parameter, and its shadow changes from being oblate to being sharp by increasing in the spin parameter. Comparing the calculated vertical angular diameter of the shadow with that of M87*, we found that the latter may possess about $10^36$ protons as its source of electric charge, if it is a rotating charged Weyl black hole. A complete derivation of the ergosphere and the static limit is also presented.