The interaction between feedback from active galactic nuclei and supernovae

TL;DR

This paper investigates how feedback from active galactic nuclei and supernovae interact, revealing that their combined effects on galaxy formation are less than additive, which impacts galaxy evolution models.

Contribution

It demonstrates that AGN and supernova feedback mutually weaken each other's effects, emphasizing the need for their joint inclusion in galaxy formation models.

Findings

Feedback from AGN and SNe reduces star formation together.

The mutual weakening effect can be up to an order of magnitude.

Results impact semi-analytic models and hydrodynamical simulations.

Abstract

Energetic feedback from supernovae (SNe) and from active galactic nuclei (AGN) are both important processes that are thought to control how much gas is able to condense into galaxies and form stars. We show that although both AGN and SNe suppress star formation, they mutually weaken one another's effect by up to an order of magnitude in haloes in the mass range for which both feedback processes are efficient (10^11.25 M_sun < m_200 < 10^12.5 M_sun). These results demonstrate the importance of the simultaneous, non-independent inclusion of these two processes in models of galaxy formation to estimate the total feedback strength. These results are of particular relevance to semi-analytic models, which implicitly assume the effects of the two feedback processes to be independent, and also to hydrodynamical simulations that model only one of the feedback processes.