Shadows for Kerr-Sen-Taub-NUT black holes with Manko-Ruiz parameter

Abstract

In this paper, we explore the Kerr-Sen-Taub-NUT spacetime with the inclusion of the Manko-Ruiz parameter. We demonstrate the separability of the Hamilton-Jacobi equation for a classical test particle in this spacetime and, using the null Hamilton-Jacobi equation, derive a set of equations that define the black hole shadow boundary. Our analysis reveals that the shadow shape is influenced by variations in the spacetime parameters, including the Hassan-Sen transformation parameter, which corresponds to the black hole electric charge, as well as the NUT charge and rotational parameter. Additionally, we highlight the impact of the Manko-Ruiz parameter on the shadow deformation, offering new insights into its role in shaping the Kerr-Sen-Taub-NUT spacetime geometry.