Parameter estimation of Kerr-Bertotti-Robinson black holes using their shadows

Abstract We investigate the shadow of Kerr-Bertotti-Robinson black holes (KBRBHs), which have a deviation parameter B that captures the effect of an external magnetic field on the spacetime geometry. These spacetimes of Petrov type D are asymptotically non-flat. We utilise the separability of the Hamilton-Jacobi equation to generate null geodesics and examine the crucial impact parameters for unstable photon orbits that define the black hole shadow. We carefully investigate how the magnetic field strength B and spin parameter a influence black hole shadows, discovering that increasing B increases the shadow size while also introducing additional distortions, especially at high spins. We calculate the shadow…