Study of accretion disks around black holes with two types of gas inflows

TL;DR

This study models accretion disks around black holes using hydrodynamic equations, exploring how different gas inflow types and initial temperatures influence disk structure and emissions.

Contribution

It introduces a classification of inflowing gases into cold and hot modes based on energy parameters, highlighting the role of initial temperature in accretion dynamics.

Findings

Identification of cold and hot inflow modes in the OBC-plane

Initial temperature affects disk structure and optical depth

Potential impact on radiative emission characteristics

Abstract

We utilized steady-state, axisymmetric, viscous hydrodynamic fluid equations around a black hole in a Schwarzschild geometry background. Here, the relativistic Schwarzschild geometry is mimicked by the Paczy{\'n}sky-Wiita potential. We investigated two types of inflowing gases that can generate different kinds of accretion flows around the central objects. The inflowing gases are presented on the local energies ($B_{ob}$) of the gases versus the outermost accretion boundary locations ($r_{ob}$) plane we named it the outermost boundary condition (OBC)-plane. Based on the energies of the inflowing gases we found two types of inflowing gas classified as cold-mode and hot-mode inflowing gases in the OBC-plane. Doing so we have found the initial temperature of the inflowing gases can be a parameter for the study of the accretion process. As it can affect the disk structure and optical depth of the accretion flow, which in turn can impact the radiative emissions observed in many accreting sources.