Shadow of a nonlinear electromagnetic generalized Kerr-Newman-AdS black hole

TL;DR

This paper studies the shadow of a nonlinear electrodynamics-coupled Kerr-Newman-AdS black hole, analyzing how parameters like spin and charge affect the shadow and comparing results with Event Horizon Telescope observations.

Contribution

It introduces a detailed analysis of black hole shadows in a nonlinear electrodynamics context, incorporating finite-distance observer effects and observational constraints.

Findings

Shadow size and shape depend on spin, charge, and nonlinearity.

Observational data constrains the model parameters.

Nonlinear electrodynamics influences black hole evaporation and shadow features.

Abstract

In this work, we investigate the shadow properties of the Kerr-Newman-Anti-de Sitter black hole coupled to a nonlinear electrodynamics. We construct the shadow by employing the celestial coordinate approach for observers located at finite distances, accounting for the non-asymptotically flat nature of the spacetime. The size, distortion, area, and oblateness of the shadow are analyzed in terms of the black hole parameters, including the spin, effective charge, and nonlinearity parameter. We further explore observational constraints using the Event Horizon Telescope results for M87* and Sgr~A*. The angular diameters inferred from the observed images allow us to bound the parameter space of the model, showing that both spin and nonlinearity play key roles in shaping the shadow and in restricting the effective charge. Additionally, we examine the energy emission rate derived from the shadow radius and Hawking temperature, highlighting the influence of rotation and nonlinear electrodynamics on black hole evaporation. Our results demonstrate that the black hole model provides a physically consistent and observationally viable extension of the standard Kerr paradigm, with potential implications for near-horizon quantum processes and tests of gravity beyond general relativity.