Spherical Accretion Flow onto General Parameterized Spherically Symmetric Black Hole Spacetimes

Abstract

The transonic phenomenon of black hole accretion and the existence of the photon sphere are the characteristics of strong gravitational fields near a black hole horizon. In this work, we study spherical accretion flow onto a general parametrized spherically symmetric black hole spacetimes.For this purpose, we analyze the accretion process of various perfect fluids, such as the isothermal fluid of ultra-stiff, ultra-relativistic, and sub-relativistic types and polytropic fluid, respectively. The influences of extra parameters beyond the Schwarzschild black hole in the general parameterized spherically symmetric black hole on the flow behaviors of the above-mentioned test fluids are studied in detail. In addition, by studying the accretion of ideal photon gas, we further discuss the correspondence between the sonic radius of accreting photon gas and the photon sphere for the general parameterized spherically symmetric black hole. Some possible future extensions of our analysis are also discussed.

Shadows of parametrized axially symmetric black holes allowing for separation of variables

“…There is also the strict hierarchy of orders of expansion, so that one can always distinguish the dominant parameters. As the only general black-hole parametrization it attracted considerable interest during the past few years and various effects were studied for such generalized description of black hole spacetimes [45][46][47][48][49][50][51][52].…”