Observational Features of Thin Accretion Disk Around Rotating Regular Black Hole

TL;DR

This paper explores how a regularization parameter in rotating regular black holes affects observable features of thin accretion disks, revealing significant impacts on radiation efficiency and black hole imaging, especially for rapid spins and high inclinations.

Contribution

It introduces the effects of an exponential regularization parameter on accretion disk observables around rotating regular black holes, extending beyond Kerr black hole models.

Findings

Regular parameter increases radiation efficiency.

Contracts black hole lensing bands.

Effects are more pronounced at high spins and inclinations.

Abstract

Rotating regular black hole, as a promising extension beyond general relativity, offer a phenomenological model that resolves spacetime singularities. In this study, we investigate the observational features of thin accretion disk around a well-known rotating regular black hole, which introduce an exponential converge factor $e^{-k/r}$ to the black hole mass M, where $k$ is the regular parameter. By studying the effects of the regular parameter on key quantities such as energy, angular momentum, and the innermost stable circular orbits of a test particle, we are able to analyze the radiative flux, temperature, and differential luminosity of the thin accretion disk in this rotation regular black hole spacetime. By using the ray-tracing method, we also obtain the bolometric images of thin accretion disk around this rotating regular black hole, with various black hole spins and inclination angels. Our results show that the regular parameter significantly impacts the observables, enhancing the radiation efficiency of thin accretion disk and contracting the lensing bands of black hole image, compared to Kerr black hole. These effects become more pronounced for rapidly rotating regular black hole and large inclination angels, making them more detectable in astrophysical observations.