Review: Accretion Disk Theory

TL;DR

This paper reviews the fundamental concepts of accretion disk theory, emphasizing black hole accretion, evaluating the alpha-model, exploring alternative turbulence prescriptions, and presenting a simple self-gravitating disk model with observational evidence.

Contribution

It provides a comprehensive review of accretion disk models, compares the alpha-model with Reynolds number-based turbulence prescriptions, and introduces a simple self-gravitating disk model.

Findings

Alpha-model has notable strengths and weaknesses.

Reynolds number-based turbulence may enhance understanding.

Observational evidence supports self-gravitating disk models.

Abstract

In this paper I review and discuss the basic concepts of accretion disks, focused especially on the case of accretion disks around black holes. The well known alpha-model is revisited, showing the strengths and weaknesses of the model. Other turbulent viscosity prescription, based on the Reynolds number, that may improve our understanding of the accretion paradigm is discussed. A simple but efficient mathematical model of a self-gravitating accretion disk, as well as observational evidence of these objects, are also included.