Stellar and quasar feedback in concert: effects on AGN accretion, obscuration, and outflows

We study the interaction of feedback from active galactic nuclei (AGN) and a multiphase interstellar medium (ISM), in simulations including explicit stellar feedback, multiphase cooling, accretion-disc winds, and Compton heating. We examine radii similar to 0.1-100 pc around a black hole (BH), where the accretion rate on to the BH is determined and where AGN-powered winds and radiation couple to the ISM. We conclude: (1) the BH accretion rate is determined by exchange of angular momentum between gas and stars in gravitational instabilities. This produces accretion rates similar to 0.03-1M(circle dot) yr(-1), sufficient to power luminous AGN. (2) The gas disc in the galactic nucleus undergoes an initial burst of star formation followed by several million years where stellar feedback suppresses the star formation rate (SFR). (3) AGN winds injected at small radii with momentum fluxes similar to LAGN/c couple efficiently to the ISM and have dramatic effects on ISM properties within similar to 100 pc. AGN winds suppress the nuclear SFR by factors similar to 10-30 and BH accretion rate by factors similar to 3-30. They increase the outflow rate from the nucleus by factors similar to 10, consistent with observational evidence for galaxy-scale AGN-driven outflows. (4) With AGN feedback, the predicted column density distribution to the BH is consistent with observations. Absent AGN feedback, the BH is isotropically obscured and there are not enough optically thin sightlines to explain type-I AGN. A 'torus-like' geometry arises self-consistently as AGN feedback evacuates gas in polar regions.