Thermal Stability of Magnetized, Optically Thin, Radiative Cooling-dominated Accretion Disks

TL;DR

This paper analyzes the thermal stability of optically thin, radiative cooling-dominated accretion disks, revealing magnetic fields can stabilize disks previously thought unstable, with implications for astrophysical outflows and X-ray binary behaviors.

Contribution

It demonstrates that magnetic fields can stabilize radiative cooling-dominated accretion disks, extending previous stability analyses and offering new explanations for observed astrophysical phenomena.

Findings

Magnetic fields can stabilize thermally unstable disks.

Disks without magnetic fields are thermally unstable.

Results may explain differences in X-ray binary behaviors.

Abstract

We investigate the thermal stability of optically thin, two-temperature, radiative cooling-dominated accretion disks. Our linear analysis shows that the disk is thermally unstable without magnetic fields, which agrees with previous stability analysis on the Shapiro-Lightman-Eardley disk. By taking into account the effects of magnetic fields, however, we find that the disk can be or partly be thermally stable. Our results may be helpful to understand the outflows in optically thin flows. Moreover, such radiative cooling-dominated disks may provide a new explanation of the different behaviors between black hole and neutron star X-ray binaries on the radio/X-ray correlation.