Shadow cast and deflection of light by charged rotating regular black holes

TL;DR

This paper investigates the properties, shadow, and gravitational lensing of charged rotating regular black holes, revealing how charge influences observable features and constraining parameters using M87* data.

Contribution

It introduces a comprehensive analysis of charged rotating regular black holes, extending Kerr and Kerr-Newman models, and explores their shadow and lensing characteristics with observational constraints.

Findings

Shadow size decreases with increasing charge Q.

Shadow distortion increases with charge Q.

Deflection angle decreases as black hole charge increases.

Abstract

We discuss the horizon properties, shadow cast, and the weak gravitational lensing of charged rotating regular black holes, which in addition to mass ($M$) and rotation parameter ($a$) have an electric charge ($Q$) and magnetic charge ($g$). The considered regular black holes are the generalization of the Kerr ($Q=g=0$) and Kerr-Newman ($g=0$) black holes. Interestingly, for a given parameter set, the apparent size of the shadow monotonically decreases and the shadow gets more distorted with increasing charge parameter $Q$. We put constraints on the black hole parameters with the aid of recent M87* shadow observation. The conserved quantities associated with the rotating regular black holes are calculated and also a brief description of the weak gravitational lensing using the Gauss-Bonnet theorem is presented. Interestingly, the deflection angle decreases with the charge of the black hole. Our results \textit{vis-\`{a}-vis} go over to the Kerr and Kerr-Newman black holes in the appropriate limits.