Rotating Black Holes Surrounded by Massive Vector Fields in Kaluza Klein Gravity

Abstract

In this paper, we introduce a rotating Kaluza-Klein black hole characterized by a massive vector field and a scalar field. We begin by identifying the horizons and mapping the allowed parameter space to differentiate black hole solutions from naked singularities. The thermodynamic analysis shows a phase transition by examining Hawking temperature and heat capacity. We also conduct a topological study of the thermodynamic potentials. The Hawking temperature indicates a conventional critical point, while the off-shell generalized free energy classifies the system into a specific universal group. We further investigate the geometry of the ergosphere and how it relates to the black holes spin. Additionally, we look at astrophysical signs, such as the black hole shadow and the features of the thin accretion disk. Our results indicate that while the extra-dimensional changes significantly shift phase transition points and modify the shadow size, the essential topological class remains stable. This study provides a solid framework for distinguishing higher-dimensional gravity models through both thermodynamic and observational signs.