Trajectory of light ray slightly above the equatorial plane in Kerr geometry and its deflection

Abstract

Deflection angle for a light ray travelling in the equatorial plane of a rotating Kerr mass has been calculated in the past by various investigators. Considering the light ray to be travelling only slightly above the equatorial plane, calculations have been made in the present paper for such a ray’s deflection angle. We calculate deflection angles for the light ray at various heights above the equatorial plane, which are small compared to the impact parameter and derive corresponding analytical expressions for deflection angle.