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arXiv · 1909.01988

Shadow of charged black holes in Gauss-Bonnet gravity

Anish Das·Ashis Saha·Sunandan Gangopadhyay
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Abstract

In this paper, we investigate the effect of higher curvature corrections from Gauss-Bonnet 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 Hamilton-Jacobi 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 Gauss-Bonnet parameter $γ$ on the radius of the shadow $R_s$ is studied in detail. It is observed that the Gauss-Bonnet 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 Gauss-Bonnet 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 Gauss-Bonnet parameter $γ$ on the energy emission rate of the black hole which depends on the black hole shadow radius and represent the results graphically.

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Anish Das, Ashis Saha, Sunandan Gangopadhyay. 2019-09-04. Shadow of charged black holes in Gauss-Bonnet gravity. https://doi.org/10.1140/epjc%2Fs10052-020-7726-z

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