We study thin accretion disks in the gravitational field of a class of rotating regular black holes. Our objective is to determine the key parameters governing these accretion disks: the radius of the innermost stable circular orbit $$(r_{\textrm{ISCO}})$$( r ISCO ) and the efficiency $$(\eta )$$( η ) of the accretion disk in converting matter into radiation. We employ a simplified model to describe the disk’s radiative flux, and differential and spectral luminosity. Subsequently, we compare our findings with the expectations from accretion disks around Kerr black holes. Notably, our calculations reveal that both the luminosity of the accretion disk and its efficiency are greater when considering the geometry of rotating regular black holes, particularly for fixed and small values of the spin parameter (j), in contrast to the predictions obtained using the Kerr metric for a black hole of the same mass. These results offer intriguing insights into the behavior of astrophysical black holes.

A non-extreme dilatonic charged (by two “color electric” charges) black hole solution is examined within a four-dimensional gravity model that incorporates two scalar (dilaton) fields and two Abelian vector fields. The scalar and vector fields interact through exponential terms containing two dilatonic coupling vectors. The solution is characterized by a dimensionless parameter a $$(0< a < 2)$$( 0 < a < 2 ) , which is a specific function of dilatonic coupling vectors. The paper presents solutions for timelike and null circular geodesics that may play a crucial role in different astrophysical scenarios, including quasinormal modes of various test fields in the eikonal approximation. For $$a = 1/2,1, 3/2,2 $$a = 1 / 2 , 1 , 3 / 2 , 2 , the radii of the innermost stable circular orbit are presented and analyzed.

Our research focuses on examining the characteristics of thin accretion disks encircling rotating regular black holes. In this study, we investigate the important features of accretion disks surrounding Bardeen's regular black holes, which play a crucial role in addressing the singularity issue. The horizon configuration of rotating Bardeen black holes is analyzed in details, as well as the innermost stable circular orbits related to this spacetime. The primary goal is to derive quantitively the radiative flux, differential and spectral luminosities of the accretion disk. Within the specified gravitational field, particularly, by taking the parameter r_0*>0 and fixing the j=0.2, our findings show that the corresponding accretion disk’s luminosity exceeds that one predicted by the Kerr metric at identical value of spin parameter ( j=0.2). Making the juxtaposition of Bardeen’s black hole parameter with the spin parameter of the Kerr black hole we reveal that the spacetime corresponding to the non-rotating Bardeen black holes, in some certain cases, can imitate the Kerr spacetime.