Spherical Accretion Flow onto General Parameterized Spherically Symmetric Black Hole Spacetimes

TL;DR

This paper investigates spherical accretion flows onto general parametrized spherically symmetric black holes, analyzing fluid behaviors and the relation between sonic radius and photon sphere, extending understanding beyond Schwarzschild black holes.

Contribution

It introduces a comprehensive analysis of accretion flows onto parametrized black holes, including various fluids and the connection between sonic radius and photon sphere.

Findings

Accretion behaviors vary with extra parameters of the black hole.

The sonic radius of photon gas correlates with the photon sphere.

Influences of different fluid types on accretion dynamics are characterized.

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.