Study of circular geodesics and shadow of rotating charged black hole surrounded by perfect fluid dark matter immersed in plasma

TL;DR

This paper investigates the impact of perfect fluid dark matter and plasma on the null geodesics and shadow of a rotating charged black hole, providing insights into observational signatures and parameter bounds.

Contribution

It analyzes how dark matter and plasma parameters influence black hole shadows and derives bounds from observational data, extending previous models to more realistic astrophysical environments.

Findings

Black hole shadow size varies with dark matter and plasma parameters.

Plasma distribution significantly affects photon effective potential.

Bounds on plasma parameters are derived from M87* observations.

Abstract

In this work, we consider a rotating charged black hole surrounded by perfect fluid dark matter. We consider the system to be immersed in non-magnetised, pressureless plasma. First, we evaluate the null geodesics in order to study the co-rotating and counter rotating photon orbits. Further, we analyse the null geodesics to calculate the celestial coordinates ($\alpha, \beta$). The celestial coordinates are used to determine the black hole shadow radius ($R_s$). Thereafter, we observe and analyse the effects of black hole spacetime, perfect fluid dark matter and plasma parameters ($a$, $Q$, $\chi$, $k$) on the black hole shadow in detail. Finally, we study the effect of plasma distribution on the effective potential ($V_{eff}$) of the black hole spacetime as encountered by the photons. We also present bounds on the plasma parameter from the observational data from $M87^{*}$ central supermassive black hole.