Impact of plasma on the shadow of a charged spherically symmetric black hole

Abstract

The purpose of this paper is to study the impact of plasma on the shadow of a charged, static and spherically symmetric black hole in f(R) gravity. Plasma surrounding black holes can affect the propagation of light rays, influencing the observed shape and size of the black hole shadow. To explore this phenomenon, we formulate the radius of photon sphere, the angular size of the shadow and radius of shadow in low-density plasma. We find that the size of shadow becomes smaller in the presence of plasma. The observed reduction in the size of the shadow in the presence of plasma can be attributed to the interaction between light and the plasma medium. The study of the rate of energy emission is also investigated in the presence of plasma medium and we find the peak position shifts from high to low frequency. The reduction in the rate of energy emission due to plasma can affect the dynamics of these accretion disks. We explore the angular radius for distant observer which has a decreasing behavior.