The Effect of Halo Mass on the HI Content of Galaxies in Groups and
  Clusters
  We combine data from the Sloan Digital Sky Survey (SDSS) and the Arecibo
Legacy Fast ALFA Survey (ALFALFA) to study the cold atomic gas content of
galaxies in groups and clusters in local universe. A careful cross-matching of
galaxies in the SDSS, ALFALFA and SDSS group catalogs provides a sample of
group galaxies with stellar masses $10^{8.4} M_{\odot} \le M_{*} \le 10^{10.6}
M_{\odot}$ and group halo masses $10^{12.5} h^{-1} M_{\odot} \le M_h \le
10^{15.0} h^{-1} M_{\odot}$. Controlling our sample in stellar mass and
redshift, we find no significant radial variation in the galaxy \hi\
gas-to-stellar mass ratio for the halo mass range in our sample. However, the
fraction of galaxies detected in ALFALFA declines steadily towards the centers
of groups with the effect being most prominent in the most massive halos. In
the outskirts of massive halos a hint of a depressed detection fraction for low
mass galaxies suggests pre-processing that decreases the \hi\ in these galaxies
before they fall into massive clusters. We interpret the decline in the ALFALFA
detection of galaxies in the context of a threshold halo mass for ram pressure
stripping for a given galaxy stellar mass. The lack of an observable decrease
in the galaxy \hi\ gas-to-stellar mass ratio with the position of galaxies
within groups and clusters highlights the difficulty of detecting the impact of
environment on the galaxy \hi\ content in a shallow \hi\ survey.
