Fast and energetic AGN-driven outflows in simulated dwarf galaxies
  The systematic analysis of optical large-scale surveys has revealed a
population of dwarf galaxies hosting AGN, which have been confirmed by X-ray
follow-up observations. Recently, the MaNGA survey identified six dwarf
galaxies that appear to have an AGN that is preventing on-going star formation.
It is therefore timely to study the physical properties of dwarf galaxies, in
particular whether the presence of an AGN can affect their evolution. Using the
moving mesh code AREPO, we have investigated different models of AGN activity,
ranging from simple energy-driven spherical winds to collimated, mass-loaded,
bipolar outflows in high resolution simulations of isolated dwarf galaxies
hosting an active black hole. Our simulations also include a novel
implementation of star formation and mechanical supernova (SN) feedback. We
find that AGN outflows have a small but systematic effect on the central star
formation rates (SFRs) for all set-ups explored, while substantial effects on
the global SFR are only obtained with strong SNe and a sustained
high-luminosity AGN with an isotropic wind. This suggests that AGN feedback in
dwarf galaxies is unlikely to directly regulate their global SFRs. There is,
however, a significant effect on outflow properties, which are notably enhanced
by the AGN to much higher outflow temperatures and velocities, in agreement
with kinematic signatures from the MaNGA survey. This indicates that AGN may
play an indirect role in regulating the baryon cycle in dwarf galaxies by
hindering cosmic gas inflows.
