Shadows and optical appearance of a power-Yang-Mills black hole surrounded by different accretion disk profiles

Abstract

In the present work, we investigate the image of a power-Yang-Mills black hole and its luminosity under distinctive accretion models. Meanwhile, a special emphasis is put on the different image characteristics of the distant observer when the related physical quantity of the black hole varies. Concretely, after showing the power Yang-Mills black hole's relevance with the Event Horizon Telescope data, we unveil the impact of the power parameter $\ensuremath{\gamma}$ on the photon trajectories, the observed intensity, and consequently on the image formation of such black hole. Furthermore, we establish that for the thin disk accretion model that the shadow, lens ring, and photon ring appear near the black hole following some parameter impact ranges. We also show that due to the extreme demagnetization, the remote observer cannot obtain the observation flux provided by the photon ring. Hence, the intensity of observation is provided by the direct image from accretion, and the lens ring also contributes, but only a small part. In addition, different emission profiles of the accretion will also directly affect the observed specific intensity. Such investigations have been realized within a variety of $\ensuremath{\gamma}$'s values. Later, the spherical infalling accretion model is considered and discussed within the $\ensuremath{\gamma}$ variation and by paying attention to the conformally invariant case associated with $\ensuremath{\gamma}=\frac{3}{4}$. Lastly, one concludes that the black hole presents a larger intensity as the power parameter $\ensuremath{\gamma}$ increases. In a word, observational appearances of the power Yang-Mills black hole surrounded by various accretions present some nice features that can be used to distinguish black holes from different gravity theories.