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

TL;DR

This paper studies the effects of dark matter halos and plasma on the observational properties of Schwarzschild black holes, including lensing and shadow features, using theoretical analysis and EHT data.

Contribution

It introduces a detailed analysis of black hole spacetime with dark matter and plasma effects, including ISCO, photon sphere, and shadow modifications, constrained by observational data.

Findings

ISCO radius increases with spacetime parameters

Plasma affects black hole shadow size and shape

EHT data constrains black hole parameters

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.