Investigating the shadows of new regular black holes with a Minkowski core: Effects of spherical accretion and core type differences

TL;DR

This study explores the shadows and optical appearances of a new class of regular black holes with a Minkowski core, analyzing how quantum gravity parameters and core types influence observable features under different accretion scenarios.

Contribution

It introduces a novel regular black hole model based on the GUP, comparing its shadow features with traditional models and analyzing the effects of core type and accretion on observables.

Findings

Shadow and photon sphere radii decrease with increasing $eta_0$

Observed specific intensity increases with $eta_0$

Differences in shadows are more pronounced with larger $eta_0$ and core type variations

Abstract

We investigated the shadows and optical appearances of a new type of regular black holes (BHs) with a Minkowski core under various spherical accretion scenarios. These BHs are constructed by modifying the Newtonian potential based on the minimum observable length in the Generalized Uncertainty Principle (GUP). They correspond one-to-one with traditional regular BHs featuring a de-Sitter (dS) core (such as Bardeen/Hayward BHs), characterized by a quantum gravity effect parameter ($\alpha_0$) and spacetime deformation factor ($n$). We found that the characteristic parameters give rise to some novel observable features. For these new BHs, both the shadow and photon sphere radii decrease with the increase in $\alpha_0$, while the observed specific intensity increases. Conversely, as n increases, the shadow and photon sphere radii increase, while the observed specific intensity decreases. Under different spherical accretion scenarios, the shadows and photon sphere radii remain identical; however, the observed specific intensity is greater under static spherical accretion than under infalling spherical accretion. Additionally, we found that these regular BHs with different cores exhibit variations in shadows and optical appearances, particularly under static spherical accretion. Compared with Bardeen BH, the new BHs exhibit a lower observed specific intensity, a dimmer photon ring, and smaller shadow and photon sphere radii. Larger values of $\alpha_0$ lead to more significant differences, and a similar trend was also observed when comparing with Hayward BH. Under infalling spherical accretion, the regular BHs with different cores exhibit only slight differences in observed specific intensity, which become more evident when $\alpha_0$ is relatively large.