Contribution of the cosmological constant to the bending of light in Kerr–de Sitter spacetime

We examine the effect of the cosmological constant $\Lambda$ on the angle of deflection of null geodesics in the equatorial plane of the Kerr–de Sitter spacetime. This is done by employing a procedure used recently by Rindler and Ishak to obtain the bending angle of light in the Schwarzschild–de Sitter geometry. We show that this approach yields a contribution from the cosmological constant in the expression for the bending angle.

Figure 1

The plane graph corresponding to the orbit in (10) with the one-sided deflection angle given by $ϵ=\psi -\varphi$ (adapted from 18).