Removal and mixing of the coronal gas from satellites in galaxy groups:
  cooling the intragoup gas
  The existence of an extended hot gaseous corona surrounding clusters, groups
and massive galaxies is well established by observational evidence and
predicted by current theories of galaxy formation. When a small galaxy collides
with a larger one, their coronae are the first to interact, producing
disturbances that remove gas from the smaller system and settle it into the
corona of the larger one. For a Milky-Way-size galaxy merging into a low-mass
group, ram pressure stripping and the Kelvin-Helmholtz instability are the most
relevant of these disturbances. We argue that the turbulence generated by the
latter mixes the material of both coronae in the wake of the orbiting satellite
creating a "warm phase" mixture with a cooling time a factor of several shorter
than that of the ambient intragroup gas. We reach this conclusion using
analytic estimates, as well as adiabatic and dissipative high resolution
numerical simulations of a spherical corona subject to the ablation process of
a constant velocity wind with uniform density and temperature. Although this is
a preliminary analysis, our results are promising and we speculate that the
mixture could potentially trigger in situ star formation and/or be accreted
into the central galaxy as a cold gas flow resulting in a new mode of star
formation in galaxy groups and clusters.
