Stabilization of radiation pressure dominated accretion disks by viscous fluctuations

TL;DR

This paper investigates whether stochastic viscous fluctuations in turbulent accretion disks can stabilize radiation pressure dominated regions, potentially resolving a long-standing instability problem in accretion disk theory.

Contribution

The study proposes that viscous fluctuations can stabilize radiation pressure dominated accretion disks, offering a new perspective on their observed variability.

Findings

Viscous fluctuations can suppress large amplitude oscillations.

Stochastic variability may explain observed stability in certain accretion disks.

Potential resolution to the radiation pressure instability problem.

Abstract

The standard thin accretion disk model has been successfully used to explain the soft X-ray spectra of Galactic black hole systems and perhaps the UV emission of Active Galactic Nuclei. However, radiation pressure dominated disks are known to be viscously unstable and should produce large amplitude oscillations that are typically not observed. Instead, these sources exhibit stochastic variability which may naturally arise due to viscous fluctuations in a turbulent disk. Here we investigate whether these aperiodic viscous fluctuations can stabilize the inner radiation pressure dominated disks and hence maybe the answer to a forty year old problem in accretion disk theory.