  We report on the merger-induced generation of a shock-heated gas wind and
formation of a remnant gas halo in simulations of colliding disk galaxies. The
simulations use cosmologically motivated initial conditions and include the
effects of radiative cooling, star formation, stellar feedback and the
non-adiabatic heating of gas. The non-adiabatic heating, i.e. shocks, generated
in the final merger forces gas out of the central region of the merger remnant
and into the dark-matter halo. We demonstrate that the amount of heating
depends on the size of the progenitor disk galaxy as well as the initial orbit
the galaxies are placed on. Based upon these dependencies, we motivate a
possible recipe for including this effect in semi-analytic models of galaxy
formation.
