Accretion Disc Outbursts and Stability Analysis

TL;DR

This paper reviews the mechanisms behind accretion disc outbursts in astrophysical systems, emphasizing the importance of time-dependent models and the hierarchy of timescales in understanding disc instabilities and their observational signatures.

Contribution

It provides an overview of accretion disc outburst phenomena and highlights the significance of incorporating multiple timescales in stability analysis.

Findings

Accretion disc outbursts are linked to instabilities driven by various timescales.

Time-dependent models are essential for understanding outburst mechanisms.

Hierarchy of dynamical, viscous, and thermal timescales influences disc stability.

Abstract

Accretion disc outbursts are re-occurring events observed in various astrophysical systems, including X-ray binaries and cataclysmic variables. These outbursts are characterized by a sudden increase in luminosity due to various instabilities in the accretion disc. We need to investigate the time-dependent accretion flow models to understand the mechanisms driving these outbursts. Time-dependent models incorporate the disc's time evolution and can capture the build-up of instabilities. This review aims to give a basic overview of accretion disc outburst and stability analysis. The paper highlights the necessity of considering the hierarchy of different timescales, dynamical, viscous, and thermal, when investigating the instabilities occurring in the accretion disc. The importance and observational implications of studying these accretion disc outbursts are also discussed.