Gravitational Faraday rotation of light propagation in the Kerr-Newman-Taub-NUT space-time

TL;DR

This paper studies how light's polarization rotates due to gravity in a complex black hole spacetime, revealing a non-zero effect influenced by black hole properties and observer position, contrary to prior assumptions.

Contribution

It demonstrates a non-zero gravitational Faraday rotation in Kerr-Newman-Taub-NUT spacetime, extending previous zero-effect results and highlighting the roles of charge and NUT parameters.

Findings

Non-zero Faraday rotation found in the weak deflection limit.

Rotation depends on black hole spin, mass, charge, and NUT charge.

Additional contributions from electrical and NUT charges identified.

Abstract

We investigate the gravitational Faraday effect in the Kerr-Newman-Taub-NUT space-time under the weak deflection limit. Contrary to previously stated zero net effect when the source and the observer are remote from the black hole, a non-zero Faraday rotation has been found. The rotation angle is dependent on the spin and the mass of the black hole and the observer's angular position, as in the case of the Kerr space-time, with additional contribution of the electrical charge and the NUT charge.