Light deflection due to a charged, rotating body

According to the general theory of relativity 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 the space–time geometry of a charged, rotating body on the motion of the light ray. We obtained the expression for the equatorial deflection of light due to such a body up to the fourth-order contribution of both the mass and charge. We used the null geodesic approach of the light ray for our calculation. If we set the charge equal to zero, our expression of the bending angle is reduced to the Kerr equatorial bending angle. If we set the rotation to zero, our expression reduces to the Reissner–Nordström deflection angle, and if we set both charge and rotation to zero, our expression reduces to the Schwarzschild bending angle. (paper)