Viscous time lags between starburst and AGN activity

TL;DR

This paper introduces a viscous time lag in gas flow through the accretion disc to explain the observed 100 Myr delay between starburst and AGN activity, aligning with black hole mass correlations.

Contribution

It extends previous models by incorporating viscous time lags, providing a better explanation for observed delays and correlations in galaxy evolution.

Findings

Reproduces observed starburst-AGN time lags.

Aligns with black hole mass and stellar velocity dispersion correlation.

Supports viscous flow as key in galaxy evolution timing.

Abstract

There is strong observational evidence indicating a time lag of order of some 100 Myr between the onset of starburst and AGN activity in galaxies. Dynamical time lags have been invoked to explain this. We extend this approach by introducing a viscous time lag the gas additionally needs to flow through the AGN's accretion disc before it reaches the central black hole. Our calculations reproduce the observed time lags and are in accordance with the observed correlation between black hole mass and stellar velocity dispersion.