Shadow of charged black holes in GaussBonnet gravity
Abstract
In this paper, we investigate the effect of higher curvature corrections from GaussBonnet gravity on the shadow of charged black holes in both AdS and Minkowski spacetimes. The null geodesic equations are computed in d =5 spacetime dimensions by using the directions of symmetries and HamiltonJacobi equation. With the null geodesics in hand, we then proceed to evaluate the celestial coordinates (α ,β ) and the radius R_{s} of the black hole shadow and represent it graphically. The effects of charge Q of the black hole and the GaussBonnet parameter γ on the radius of the shadow R_{s} is studied in detail. It is observed that the GaussBonnet parameter γ affects the radius of the black hole shadow R_{s} differently for the AdS black hole spacetime in comparison to the black hole spacetime which is asymptotically flat. In particular the radius of the black hole shadow increases with increase in the GaussBonnet parameter in case of the AdS black hole spacetime and decreases in case of the asymptotically flat black hole spacetime. We then introduce a plasma background in order to observe the change in the silhouette of the black hole shadow due to a change in the refractive index of the plasma medium. Finally, we study the effect of the GaussBonnet parameter γ on the energy emission rate of the black hole which depends on the black hole shadow radius and represent the results graphically.
 Publication:

European Physical Journal C
 Pub Date:
 February 2020
 DOI:
 10.1140/epjc/s100520207726z
 arXiv:
 arXiv:1909.01988
 Bibcode:
 2020EPJC...80..180D
 Keywords:

 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory
 EPrint:
 18 pages Latex, comments are welcome