Gravitational and electromagnetic radiation in Kerr−Maxwell spaces

The class of Kerr−Maxwell spaces is defined. This class consists of regular electrovac spacetimes in which a geodesic, diverging, shear−free principal null vector field of the Weyl tensor coincides with a principal null vector field of the Maxwell tensor. It is shown that this class admits no Petrov−Penrose type III or type N solutions. It is also shown that the most general nonradiative solution is the Kerr−Newman metric.