Momentum-driven Winds from Radiatively Efficient Black Hole Accretion and Their Impact on Galaxies

TL;DR

This study uses hydrodynamical simulations to show that black hole radiation-driven winds significantly expel gas from galaxies, suppressing accretion and altering galaxy evolution compared to models without AGN feedback.

Contribution

It introduces a detailed model of momentum-driven black hole winds in cosmological simulations, demonstrating their impact on galactic gas expulsion and accretion suppression.

Findings

Up to 80% of galactic gas can be expelled by black hole winds.

AGN feedback can suppress gas accretion by a factor of 30.

Outflow velocities reach 500-1,000 km/s, traveling several Mpc.

Abstract

We explore the effect of momentum-driven winds representing radiation pressure driven outflows from accretion onto supermassive black holes in a set of numerical hydrodynamical simulations. We explore two matched sets of cosmological zoom-in runs of 24 halos with masses ~$10^{12.0}-10^{13.4}$ M_sun run with two different feedback models. Our `NoAGN' model includes stellar feedback via UV heating, stellar winds and supernovae, photoelectric heating and cosmic X-ray background heating from a meta-galactic background. Our fiducial `MrAGN' model is identical except that it also includes a model for black hole seeding and accretion, as well as heating and momentum injection associated with the radiation from black hole accretion. Our MrAGN model launches galactic outflows which result in both `ejective' feedback - the outflows themselves which drive gas out of galaxies - and `preventative' feedback, which suppresses the inflow of new and recycling gas. As much as 80 % of outflowing galactic gas can be expelled, and accretion can be suppressed by as much as a factor of 30 in the MrAGN runs when compared with the NoAGN runs. The histories of NoAGN galaxies are recycling-dominated, with ~70% of material that leaves the galaxy eventually returning, and the majority of outflowing gas re-accretes on 1 Gyr timescales without AGN feedback. Outflowing gas in the MrAGN runs has higher characteristic velocity (500 - 1,000 km/s versus 100-300 km/s for outflowing NoAGN gas) and travels as far as a few Mpcs. Only ~10% of ejected material is re-accreted in the MrAGN galaxies.