Light defection due to a charged, rotating body

TL;DR

This paper derives an expression for the deflection of light by a charged, rotating body in spacetime, showing how charge and rotation influence light bending, extending classical results in general relativity.

Contribution

It provides a new analytical expression for light deflection around a charged, rotating mass up to fourth order, unifying and extending previous models like Kerr and Schwarzschild.

Findings

Charge affects the light deflection path.

The derived formula reduces to known cases when charge or rotation is zero.

Non-zero deflection occurs even for a hypothetical massless, charged, rotating body.

Abstract

According to GTR and subsequent developments in the field, it is known that there are three factors namely mass, rotation and charge that can influence the space-time geometry. Accordingly, we discuss the effect of space-time geometry of a charged, rotating body on the motion of the light ray. We obtained the expression for equatorial defection of light due to such a body up to fourth order term. In our expression for defection angle it is clear that charge can influence the path of light ray. We used the null geodesic approach of light ray for our calculation. If we set the charge to zero our expression of bending angle gets reduced to the Kerr equatorial bending angle.If we set rotation to zero our expression reduces to Resinner-Nordstr$\ddot{o}$m defection angle and if we set both charge and rotation to zero our expression reduces to Schwarzschild bending angle. However, we get non-zero bending angle for a hypothetical massless, rotating, charged body.