The Impact of AGN Feedback on Simulated Dwarf Galaxies

Sophie Koudmani(Cambridge, UK)

Oct 19, 2020

Contrary to the standard lore, there is mounting observational evidence that feedback from active galactic nuclei (AGN) may also play a role at the low-mass end of the galaxy population. In this talk, I will explore this possibility employing both isolated and cosmological simulations of dwarf galaxies. Firstly, I will present the results from our high-resolution simulations with the moving mesh code AREPO. In these isolated dwarf simulations, the AGN has only a limited direct effect on star formation rates. There is, however, a significant effect on outflows, which are notably enhanced by the AGN to much higher temperatures and velocities. This indicates that AGN may play an indirect role in quenching dwarf galaxies by hindering cosmic gas inflows. I further investigate this quenching scenario using the cosmological simulation suite FABLE. While in the local Universe the majority of AGN in dwarfs are much dimmer than the stellar component, for z ≥ 2 there is a significant population that outshines their hosts. These high-redshift overmassive BHs contribute to the quenching of dwarfs, whereas at late cosmic times supernova feedback is more efficient. I will also discuss the impact of instrument sensitivity and contamination from X-ray binaries on current X-ray searches for AGN in dwarfs and make predictions for future observations.

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