Plasma-Induced Modifications of the Shadows of Rotating Bardeen Black Holes with Perfect Fluid Dark Matter

Abstract

We study the optical appearance of a rotating regular Bardeen black hole embedded in perfect fluid dark matter (PFDM) when photon propagation occurs through a plasma medium. Three plasma models are examined: a homogeneous distribution, a radially varying distribution, and a general distribution with both radial and angular dependence. The influence of plasma on photon motion and the resulting shadow morphology is analysed using shadow observables. To assess astrophysical viability, the plasma and PFDM parameters are constrained using the Event Horizon Telescope bounds on shadow circularity and fractional diameter deviation. The results demonstrate that environmental effects arising from both PFDM and plasma produce measurable modifications to the shadow, indicating that black-hole imaging can provide useful constraints on the surrounding medium as well as the intrinsic properties of regular rotating black holes.