The trajectory of light ray under Kerr-Taub-NUT space time

TL;DR

This paper investigates how a rotating mass with a magnetic field in Kerr-Taub-NUT spacetime affects light ray trajectories, revealing that magnetism significantly influences light deflection beyond classical Kerr predictions.

Contribution

It introduces a detailed calculation of light deflection in Kerr-Taub-NUT spacetime, incorporating magnetic effects up to fourth order, which were not previously analyzed.

Findings

Magnetic fields cause noticeable deviations in light deflection.

The derived bending angle reduces to Kerr case when magnetism is zero.

Non-zero bending angles exist for hypothetical magnetic, low-mass bodies.

Abstract

According to General Relativity, there are three factors namely mass, rotation and charge that can influence the path of light ray. Many authors showed that there is another factor which can influence the path of light ray namely gravitomagnetism. Here we discuss the effect of a rotating body with non-zero (Kerr- Taub-NUT) magnetic field on the motion of light ray. We use the null geodesic of photon method and obtain the deflection angle of light ray for such a body up to fourth order term in the equatorial plane. Our calculation shows that magnetism has a noticeable effect on the path of light ray. If we set the magnetism equal to zero, our expression of bending angle reduces to the Kerr bending angle. However, we get non-zero bending angle for a hypothetical mass less, magnetic body.