The shadows and observational appearance of a noncommutative black hole surrounded by various profiles of accretions

TL;DR

This paper investigates how different accretion models and noncommutative parameters influence the shadow and observational appearance of noncommutative Schwarzschild black holes, revealing significant effects on brightness, ring structures, and image features.

Contribution

It provides a detailed analysis of black hole shadows with various accretion profiles in noncommutative geometry, highlighting the impact of noncommutative parameters on observational features.

Findings

Direct emissions dominate observed intensity with thin accretion disks.

Photon rings contribute negligibly to total brightness despite multiple intersections.

Noncommutative parameters significantly affect the size and brightness of shadow features.

Abstract

The accretion around the black hole plays a pivotal role in the theoretical analysis of black hole shadow, and of the black hole observation in particular. In this paper, we mainly study the shadow and observation characteristics of noncommutative Schwarzschild black holes wrapped by three accretion models, and then explore the influence of noncommutative parameters on the observation appearance and spacetime geometry of black holes. When the black hole is surrounded by an optically and geometrically thin accretion disk, it shows that the direct emissions always dominate the total observed intensity, while the lensing ring superimposed upon the direct emission produces a thin ring, which improves the observation intensity of the black hole image. However, the photon rings makes a negligible contributions to the total observed brightness due to its exponential narrowness, although the photon ring intersects the thin plane more than three times to pick up larger intensity. More importantly, when the noncommutative parameters changed, the corresponding regions and observation intensities of photon ring, lensing ring and direct emission all change correspondingly. For optical thin spherically symmetric accretion, we consider the static and infalling matters, respectively. We find that the observation intensity of the two spherical accretion models increase with the increase of noncommutative parameters. In addition, due to the Doppler effect of the infalling movement, the shadow image of infalling accretion is darker than that of static accretion. In a word, the different accretion models and noncommutative parameters will lead to different shadow images and optical appearances of noncommutative Schwarzschild black holes.