Geodesic dynamics and multi-inclination images of a non-minimally coupled black hole with a thin accretion disk

TL;DR

This paper explores how non-minimal coupling in Einstein-Yang-Mills black holes affects their optical appearance, orbital dynamics, and image properties, revealing notable differences from classical black hole models.

Contribution

It provides a detailed analysis of the impact of non-minimal coupling on black hole optical features and orbital structures, extending understanding beyond standard models.

Findings

Non-minimal coupling alters the ISCO and photon sphere properties.

The impact parameter range is extended compared to Schwarzschild and Reissner-Nordström black holes.

The observed black hole image intensity is weaker due to the coupling effects.

Abstract

In this paper, we investigate the optical properties of a black hole in non-minimal Einstein-Yang-Mills theory, illuminated by a thin accretion disk. In our setup, matter follows stable circular orbits outside the innermost stable circular orbit (ISCO), while inside the ISCO, it rapidly plunges into the black hole. By analyzing the orbital dynamics of massive and massless particles, we find that the properties of both the ISCO and the photon sphere significantly depend on the non-minimal coupling parameter. Moreover, compared with the Schwarzschild and Reissner-Nordstr\"{o}m black holes, the non-minimal coupling extends the range of the impact parameter and slightly enhances the redshift effect in the images. Additionally, due to the significant influence of the non-minimal coupling parameter on the event horizon, the observed intensity of this black hole image under the selected emission model ultimately turns out to be weaker than that of the other two types of black holes, regardless of the inclination angle between the accretion disk and observation planes.