On the double natured solutions to the two-temperature external soft photon comptonized accretion disks

TL;DR

This paper investigates the conditions under which two distinct steady-state solutions exist in a two-temperature, soft photon Comptonized accretion disk, highlighting the roles of viscosity, accretion rate, and radius.

Contribution

It introduces the concept of double-valued solutions in accretion disks based on viscosity and accretion rates, revealing new conditions for physical consistency.

Findings

Double solutions exist when viscosity exceeds a critical value.

Critical accretion rates depend on radius, temperature, and viscosity.

Advection dominated solutions may be physically inconsistent under certain conditions.

Abstract

We have analyzed pair production in the innermost region of a two-temperature external soft photon comptonized accretion disk. We have shown that, if the viscosity parameter is greater than a temperature and r dependent critical value, the solution to the disk equation is double valued: one, advection dominated and the other, radiation dominated. When the viscosity parameter is below this critical value, the accretion rate has to be confined within a region limited by a minimum and a maximum accretion rates in order to have two steady state solutions. These critical accretion rates are shown to be dependent on r, on the temperature and on the viscosity parameter . Depending on the combination of the parameters, the advection dominated solution may not be physically consistent.