Effect of gravitational lensing around black hole in dark matter halo in the presence of plasma

Abstract

This article is devoted to the investigation of the observational properties of the Schwarzschild black hole (BH) surrounded by a dark matter (DM) halo. Our study commences with a brief review of spacetime, including the horizon structure and curvature invariants, which are the Ricci scalar, the square of the Ricci tensor, and the Kretschmann scalar. Subsequently, we explore the massive and massless particle dynamics around the Schwarzschild BH surrounded by a dark matter halo, including the innermost stable circular orbit (ISCO) and photon sphere radii. It was found that the radius of the ISCO increases under the influence of the spacetime parameters. Additionally, we investigate the weak gravitational lensing with the assumption that the BH is surrounded by a uniform and non-uniform plasma. Finally, we examine the impact of a plasma on the BH shadow and employ Event Horizon Telescope (EHT) observational data to constrain the BH's parameters.

Figures (16)

• Figure 1: Horizon radius as a function of the halo parameters $r_s$ and $\rho_s$.
• Figure 2: Radial dependencies of the potential $V(r)$ as a function of the halo parameters $r_s$ (left panel) and $\rho_s$ (right panel).
• Figure 3: Radial dependencies of square of the specific energy $\mathcal{E}^2$ as a function of $r_s$ (left) and $\rho_s$ (right).
• Figure 4: Radial dependencies of the specific angular momentum $\mathcal{L}$ as a function of $r_s$ (left) and $\rho_s$ (right).
• Figure 5: Dependence of the ISCO radius $R_{\text{ISCO}}$ on the halo parameters $r_s$ (left) and $\rho_s$ (right).