QED Effects on Kerr-Newman Black Hole Shadows

TL;DR

This paper investigates how first-order QED effects influence the shadows of Kerr-Newman black holes with magnetic charge, revealing that QED causes the shadow area to increase by affecting photon trajectories and spacetime distortion.

Contribution

It introduces a numerical approach to analyze QED effects on black hole shadows, considering both electromagnetic and spacetime metric modifications.

Findings

QED effects enlarge the black hole shadow area.

Photons slow down in the effective medium due to QED.

QED corrections impact photon trapping and shadow shape.

Abstract

Incorporating first-order QED effects, we explore the shadows of Kerr-Newman black holes with a magnetic charge through the numerical backward ray-tracing method. Our investigation accounts for both the direct influence of the electromagnetic field on light rays and the distortion of the background spacetime metric due to QED corrections. We notice that the area of the shadow increases with the QED effect, mainly due to the fact that the photons move more slowly in the effective medium and become easier to be trapped by the black hole.