Optical Features of AdS Black Holes in the Novel 4D Einstein-Gauss-Bonnet Gravity Coupled to Nonlinear Electrodynamics

Abstract

An alternative theory of gravity that has attracted much attention recently is the novel four-dimensional Einstein-Gauss-Bonnet (4D EGB) gravity. The theory is rescaled by the Gauss-Bonnet (GB) coupling constant α→α/(D−4) in D dimensions and redefined as four-dimensional gravity in the limit D→4. Thus, in this manner, the GB term yields a non-trivial contribution to the gravitational dynamics. In fact, regularized black hole solutions and applications in the novel 4D EGB gravity have also been extensively explored. In this work, motivated by recent astrophysical observations, we present an in-depth study of the optical features of AdS black holes in the novel 4D EGB gravity coupled to exponential nonlinear electrodynamics (NED), such as the shadow geometrical shape, the energy emission rate, the deflection angle and quasinormal modes. Taking into account these dynamic quantities, we investigate the effects on the black hole solution by varying the parameters of the models. More specifically, we show that the variation of the GB and NED parameters, and of the cosmological constant, imprints specific signatures on the optical features of AdS black holes in the novel 4D EGB gravity coupled to nonlinear electrodynamics, thus leading to the possibility of directly testing these black hole models by using astrophysical observations.

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“…See e.g. [850] for a recent review of the theory, [851][852][853][854][855][856][857][858][859][860] for important discussions on possible pathologies associated to the rescaling procedure, and [861][862][863][864][865][866][867][868][869][870][871][872][873][874][875][876][877][878][879][880] for other important works on the theory. With all the caveats discussed in [851,853,[855][856][857][858][859] in mind, static spherically symmetric solutions within 4DEGB gravity have been studied, and the metric function is given by the following (see e.g.…”