Black holes surrounded by PFDM in STVG and Shadows
Abstract
In this study, we investigate the properties of black holes surrounded by Perfect Fluid Dark Matter (PFDM) within the framework of Scalar–Tensor–Vector Gravity (STVG), a prominent modified theory of gravity. By incorporating the effects of PFDM into a static and spherically symmetric black hole solution in STVG, we examine how the presence of dark matter and modifications to General Relativity affect observable astrophysical features. Special focus is given to the black hole shadow, a crucial optical signature shaped by the spacetime geometry around the event horizon. We analyze how parameters such as the PFDM density, magnetic charge, and STVG scalar fields influence the radius and shape of the shadow. Our results show that both the presence of PFDM and the modifications introduced by STVG lead to a significant enlargement of the photon sphere and observable deviations in the shadow's profile compared to standard GR predictions. These theoretical findings provide a deeper understanding of the interplay between alternative gravity models and dark matter environments and offer valuable insights for interpreting high-resolution black hole images from the Event Horizon Telescope (EHT).