Comparing Bondi and Novikov-Thorne accretion disk luminosity around regular black holes

Abstract: We consider and compare the Bondi and Novikov-Thorne accretion mechanisms in spherically symmetric regular black holes. To do so, we model the dark matter distribution adopting two main approaches. The first takes into account a cosmologically-inspired dark fluid, whose pressure turns out to be constant, whereas the density and equation of state depend on the radial coordinate. The second case employs an exponential dark matter energy distribution that describes the dark matter cloud in the accretion process. Accordingly, we quantify the mass accreted by regular solutions with the above information on the energy-momentum tensor and their luminosity and thermal properties, derived from the background models. Numerical simulations of the accretion processes are then reported, comparing regular black holes with Schwarzschild and Schwarzschild-de Sitter metrics. In so doing, we consider the Hayward, Bardeen, Dymnikova and Fang-Wang solutions, where the addiction of a further parameter determines regularity. Implications and physical consequences of using the Novikov-Thorne and Bondi accretion backgrounds are thus critically discussed in varying the free parameters of each spacetime.