Ram Pressure Stripping in Clusters and Groups

Ram pressure stripping is an important process in the evolution of both dwarf galaxies and large spirals. Large spirals are severely stripped in rich clusters and may be mildly stripped in groups. Dwarf galaxies can be severely stripped in both clusters and groups. A model is developed that describes the stripping of a satellite galaxy’s outer H i disk and hot galactic halo. The model can be applied to a wide range of environments and satellite galaxy masses. Whether ram pressure stripping of the outer disk or hot galactic halo occurs is found to depend primarily on the ratio of the satellite galaxy mass to the mass of the host group or cluster. How the effectiveness of ram pressure stripping depends on the density of the inter-group gas, the dark matter halo concentrations, and the scale lengths and masses of the satellite components is explored. The predictions of the model are shown to be well matched to H i observations of spirals in a sample of nearby clusters. The model is used to predict the range of H i gas fractions a satellite of mass Mv,sat can lose orbiting in a cluster of mass Mv,gr. Subject headings: galaxies: evolution — galaxies:clusters:general — galaxies:dwarf