AGN Accretion Discs

TL;DR

This paper explains the physics of accretion discs in active galactic nuclei, covering models, instabilities, spectral features, and related phenomena like jets and winds, aimed at graduate students.

Contribution

It provides a comprehensive overview of accretion disc physics specific to AGNs, including recent models and detailed discussions on instabilities and relativistic effects.

Findings

Models of geometrically-thin discs are detailed.

Disc instabilities and their implications are analyzed.

Discussion of thick accretion flows and related phenomena.

Abstract

I present the elements of accretion-disc physics applied to active galactic nuclei. The accretion driving mechanisms are discussed, then models of geometrically-thin discs, both stationary and time-dependent, are addressed. Disc's self-gravitation in the AGN context is presented. The shapes of spectral line from accretion discs are explained in both newtonian and relativistic cases. The physics of disc's thermal and viscous instabilities is dicussed in detail and models are applied to AGN discs. Finally, the problems of thick accretion flows (ADAFs and slim discs), disc coronae, winds and jets are discussed in some detail. This is a graduate-student level lecture, not a review article