Photon regions and shadows of Kerr-Newman-NUT black holes with a cosmological constant

We consider the Plebanski class of electrovacuum solutions to the Einstein equations with a cosmological constant. These space-times, which are also known as the Kerr-Newman-NUT-(anti-)de Sitter space-times, are characterized by a mass m, a spin a, a parameter beta that comprises electric and magnetic charge, a NUT parameter l and a cosmological constant Lambda. Based on a detailed discussion of the photon regions in these space-times (i. e., of the regions in which spherical lightlike geodesics exist), we derive an analytical formula for the shadow of a Kerr-Newman-NUT-(anti-)de Sitter black hole for an observer at given Boyer-Lindquist coordinates (r(O), theta(O)) in the domain of outer communication. We visualize the photon regions and the shadows for various values of the parameters.