The interaction between feedback from active galactic nuclei and supernovae

Energetic feedback from supernovae (SNe) and from active galactic nuclei (AGN) are both important processes that are thought to control howmuch 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 (10M8vm200v10M8). 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 the interpretation of results from hydrodynamical simulations that model only one of the feedback processes, and also to those semi-analytic models that implicitly assume the effects of the two feedback processes to be independent.