Hot accretion with outflow and thermal conduction

TL;DR

This paper develops self-similar models of advection-dominated accretion flows incorporating thermal conduction and outflows, revealing how winds and conduction influence flow dynamics, temperature, and rotation.

Contribution

It introduces a combined model of outflows and thermal conduction in accretion flows, highlighting their joint effects on flow properties, which was not previously modeled together.

Findings

Outflows cause the disc to rotate faster and become cooler.

Thermal conduction increases temperature and decreases rotational velocity.

Both winds and conduction reduce surface density and increase accretion velocity.

Abstract

We present self-similar solutions for advection -dominated accretion flows with thermal conduction in the presence of outflows. Possible effects of outflows on the accretion flow are parametrized and a saturated form of thermal conduction, as is appropriate for the weakly-collisional regime of interest, is included in our model. While the cooling effect of outflows is noticeable, thermal conduction provides an extra heating source. In comparison to accretion flows without winds, we show that the disc rotates faster and becomes cooler because of the angular momentum and energy flux which are taking away by the winds. But thermal conduction opposes the effects of winds and not only decreases the rotational velocity, but increases the temperature. However, reduction of the surface density and the enhanced accretion velocity are amplified by both of the winds and the thermal conduction. We find that for stronger outflows, a higher level of saturated thermal conduction is needed to significantly modify the physical profiles of the accretion flow.