A systematic study of AGN feedback in a disk galaxy I: global overview

TL;DR

This study uses the MACER framework to explore how AGN feedback influences galaxy evolution, showing that AGN activity correlates with star formation and can quench galaxies over about a billion years.

Contribution

First systematic analysis of AGN feedback effects in a disk galaxy incorporating cosmological inflows using the MACER framework.

Findings

AGN duty cycle of ~0.49% matches observations

Positive correlation between AGN luminosity and SFR

AGN feedback promotes cold filament formation and galaxy quenching

Abstract

This is the first paper in a series using our MACER framework to investigate the evolution of a disk galaxy, which emphasizes the role of active galactic nucleus (AGN) feedback and incorporates cosmological inflows. This paper presents the model setup and the overall results. The predicted AGN duty cycle of approximately 0.49% is consistent with observations. Analysis of the AGN luminosity and star formation rate (SFR) light curves reveals a positive correlation between the two. We find that cold filaments condense in the circumgalactic medium (CGM) region due to radiative cooling and subsequently fall onto the galaxy, significantly enhancing both the SFR and AGN activity. The galaxy is then quenched over a timescale of approximately 1 Gyr by the strong feedback from the enhanced AGN activity. This indicates that a positive correlation between SFR and AGN luminosity does not preclude AGN feedback from acting as the quenching mechanism for the galaxy. Notably, models without AGN feedback exhibit significantly lower peak SFRs than those with it. We attribute this difference to cumulative AGN feedback, which drives gas from the galaxy into the CGM, facilitating the formation of more massive cold filaments and ultimately promoting more intense starburst episodes.