The connection between AGN-driven dusty outflows and the surrounding
  environment
  Significant reservoirs of cool gas are observed in the circumgalactic medium
(CGM) surrounding galaxies. The CGM is also found to contain substantial
amounts of metals and dust, which require some transport mechanism. We consider
AGN (active galactic nucleus) feedback-driven outflows based on radiation
pressure on dust. Dusty gas is ejected when the central luminosity exceeds the
effective Eddington luminosity for dust. We obtain that a higher dust-to-gas
ratio leads to a lower critical luminosity, implying that the more dusty gas is
more easily expelled. Dusty outflows can reach large radii with a range of
velocities (depending on the outflowing shell configuration and the ambient
density distribution) and may account for the observed CGM gas. In our picture,
dust is required in order to drive AGN feedback, and the preferential expulsion
of dusty gas in the outflows may naturally explain the presence of dust in the
CGM. On the other hand, the most powerful AGN outflow events can potentially
drive gas out of the local galaxy group. We further discuss the effects of
radiation pressure of the central AGN on satellite galaxies. AGN radiative
feedback may therefore have a significant impact on the evolution of the whole
surrounding environment.
