Strong gravitational lensing by an electrically charged black hole in Eddington-inspired Born-Infeld gravity

TL;DR

This paper investigates how electric charge and coupling constants in Eddington-inspired Born-Infeld gravity influence null geodesics and strong gravitational lensing around black holes, suggesting lensing observations could test gravitational theories.

Contribution

It provides a systematic analysis of null geodesics and lensing effects in a charged black hole within Eddington-inspired Born-Infeld gravity, highlighting parameter sensitivities.

Findings

Unstable circular orbit radius decreases with coupling constant at fixed charge

Deflection angle and image magnification are highly sensitive to black hole parameters

Strong lensing observations could potentially distinguish gravitational theories

Abstract

We systematically examine the properties of null geodesics around an electrically charged, asymptotically flat black hole in Eddington-inspired Born-Infeld gravity, varying the electric charge of black hole and the coupling constant in the theory. We find that the radius of the unstable circular orbit for massless particle decreases with the coupling constant, if the value of the electrical charge is fixed. Additionally, we consider the strong gravitational lensing around such a black hole. We show that the deflection angle, the position angle of the relativistic images, and the magnification due to the light bending in strong gravitational field are quite sensitive to the parameters determining the black hole solution. Thus, through the accurate observations associated with the strong gravitational lensing, it might be possible to reveal the gravitational theory in a strong field regime.