Optical properties of black holes in the presence of a plasma: The shadow

Abstract

We have studied photon motion around axially symmetric rotating Kerr black hole in the presence of plasma with radial power-law density. It is shown that in the presence of plasma the observed shape and size of shadow changes depending on i) plasma parameters, ii) black hole spin and iii) inclination angle between observer plane and axis of rotation of black hole. In order to extract pure effect of plasma influence on black hole image the particular case of the Schwarzschild black hole has also been investigated and it has been shown that i) the photon sphere around the spherical symmetric black hole is left unchanged under the plasma influence, ii) however the Schwarzschild black hole shadow size in plasma is reduced due to the refraction of the electromagnetic radiation in plasma environment of black hole. The study of the energy emission from the black hole in plasma shows that in the presence of plasma the maximal energy emission rate from the black hole decreases.PACS numbers: 95.30.Sf; 98.62.Sb

Shadow of rotating wormhole in plasma environment

“…The solid lines correspond to the case when wormhole is in vacuum. Here we take the metric parameter to be as α = δ = γ = 0 shadow images has been recently studied in our paper (Atamurotov et al 2015). From the plots in Fig.…”

“…The shadow of the sphericallysymmetric Ellis wormholes surrounded by plasma has been studied by Perlick et al (2015). The gravitational lensing and images of black hole in plasma environment has been recently studied in Bisnovatyi-Kogan and Tsupko (2010), Tsupko and Bisnovatyi-Kogan (2012), Morozova et al (2013), Perlick et al (2015), Er and Mao (2014), Atamurotov et al (2015), Rogers (2015). The transfer of radiation in an isotropic refractive, and dispersive medium using the Hamiltonian approach in a curved spacetime is studied in Bicak and Hadrava (1975) by applying the generalrelativistic kinetic theory.…”

Horizon structure of rotating Einstein–Born–Infeld black holes and shadow

“…a dark area in front of a luminous background [56,59]. Hence, their is a significant effort to study black hole shadows and this has become a quite active research field [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] (for a review, see [60]). For the Schwarzschild black hole the shadow of the black hole is a perfect circle [60], and it is enlarged in the case of a Reissner-Nordström black hole [61].…”

“…The photons that cross the event horizon, due to strong gravity, are removed from the observable universe which lead to a shadow (silhouette) imprinted by a black hole on the bright emission that exists in its vicinity. So far the shadows of the compact gravitational objects in the different cases have been extensively studied, see, e.g., [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. Furthermore a new general formalism to describe the shadow of black hole as an arbitrary polar curve expressed in terms of a Legendre expansion was developed in a recent paper [49].…”

Shadow of a charged rotating non-commutative black hole

“…Rogers [56] explored gravitational lensing and circular orbits of the Schwarzschild BH for plasma density distributions N = 1/r h with h ≥ 0. There is a large body of literature available [57][58][59][60][61][62] on the effect of plasma on the shadows cast by the BHs.…”