Models of high-luminosity accretion disks surrounding black holes

TL;DR

This paper investigates steady-state accretion disk models around nonrotating black holes, focusing on high accretion rates, including advection effects, and analyzing the transition between optically thick and thin regions.

Contribution

It presents new global solutions for accretion disks that smoothly transition between optically thick and thin regions, highlighting the effects of different viscosity parameters.

Findings

Maximum disk temperature identified for α=0.5

No optically thin regions for α=0.1 at any accretion rate

Models include advection and generalized radiation pressure formulas

Abstract

The problem of steady-state accretion to nonrotating black holes is examined. Advection is included and generalized formulas for the radiation pressure in both the optically thick and thin cases are used. Special attention is devoted to models with a high accretion rate. Global solutions for accretion disks are studied which describe a continuous transition between an optically thick outer region and an optically thin inner region. It is shown that there is a maximum disk temperature for the model with a viscosity parameter {\alpha} = 0.5. For the model with {\alpha} = 0.1, no optically thin regions are found to exist for any accretion rate.