The Effect of Galactic Feedback on Gas Accretion and Wind Recycling
  In the absence of galactic winds, the rate at which gas accretes onto
galaxies is determined by the gravitational potential and by radiative cooling.
However, outflows driven by supernovae and active galactic nuclei not only
eject gas from galaxies, but also prevent gas from accreting in the first
place. Furthermore, gas previously ejected from a galaxy can re-accrete onto
(the same or a different) galaxy. Because this gas has a high metallicity, its
cooling rate is relatively high, which will increase its chances to re-accrete.
This complex interplay between gas inflows and outflows is discussed in this
chapter. Wind recycling is found to be an important process that fuels galaxies
at late times and the recycled gas has different properties than gas accreting
for the first time. Quantitative conclusions, however, vary between studies,
because the amount of wind recycling is dependent on the details of the
feedback model. We discuss these differences, known caveats, and ways to make
progress in understanding how galaxies are fed at low redshift.
