Ram Pressure Stripping of HI-rich Galaxies Infalling into Massive Clusters

We estimate the strength of ram pressure stripping (RPS) for H i -rich galaxies in X-ray detected clusters. We find that galaxies under stronger RPS tend to show more significantly reduced total H i mass and enhanced central SFR when compared to control galaxies in the field that have similar stellar mass, stellar surface density and integral star formation rate. Galaxies under strong or weak RPS account for ∼40% of the H i -rich population at R 200 , and even beyond R 200 in the most massive clusters. Our results imply the important role of RPS as a channel of environmental processing far before the galaxies reach the core region of clusters.