Lectures given at GH Advanced Lectures on the Starburst-AGN Connection, INAOE, June 2000, ed. D. Kunth, I. Aretxaga

Abstract: Active Galactic Nuclei are fueled from material (gas or stars) that are in general far away from the gravitational influence of the central black hole, the engine thought to be responsible for their activity. The required material has a lot of angular momentum, that is a priori quite difficult to evacuate. The various dynamical mechanisms that may play a role in this game are reviewed, including m = 2 perturbations (bars and spirals), m = 1 perturbations (spirals, warps, lopsidedness), and tidal interactions between galaxies and mergers. In the latest stages of the merger, a binary black hole could be formed, and its influence on the dynamics and fueling is discussed. Starbursts are often associated with AGN, and the nature of their particular connection, and their role in the nuclear fueling is described. Evolution of the fueling efficiency with redshift is addressed.

Table of Contents

INTRODUCTION

AGN FUELING THROUGH DENSE NUCLEAR STAR CLUSTERS

Fueling: why is there a problem?

Are stars a possible fuel?

Characteristic radii

Black hole growth by star accretion

Formation of a cusp of stars around the black hole

Stellar Collisions

LARGE-SCALE INSTABILITIES

Gravitational stability

Feedback on the dynamics

BARS

Orbits and resonances

Gas flow in barred galaxies

Angular momentum transfer

Fueling nuclear activity

Decoupling of a nuclear disk

Bars within bars

Bar destruction

Nuclear Spirals in Disk Galaxies

Bars in early- and late-types

Evolution along the Hubble sequence and growth of the black hole

m = 1 PERTURBATIONS

Physical nature of instabilities

Lopsidedness and m = 1 asymmetries

Counter-rotating components

Stability

Counter-rotation with gas

INTERACTIONS AND MERGERS

Physical processes

Gas flow and starburst/AGN triggering

OBSERVATIONAL EVIDENCE

Search for correlations between bars and AGN

Galaxy interactions and nuclear activity

Radio-galaxies

Conclusion

BLACK HOLE EVOLUTION

Black hole growth and activity life-time

Binary black hole formation

Hierarchical merging scenario

CONCLUSIONS

REFERENCES