An AzTEC 1.1-mm Survey for ULIRGs in the field of the Galaxy Cluster MS
  0451.6-0305
  We have undertaken a deep (sigma~1.1 mJy) 1.1-mm survey of the z=0.54 cluster
MS 0451.6-0305 using the AzTEC camera on the James Clerk Maxwell Telescope. We
detect 36 sources with S/N>3.5 in the central 0.10 deg^2 and present the AzTEC
map, catalogue and number counts. We identify counterparts to 18 sources (50%)
using radio, mid-infrared, Spitzer IRAC and Submillimeter Array data. Optical,
near- and mid-infrared spectral energy distributions are compiled for the 14 of
these galaxies with detectable counterparts, which are expected to contain all
likely cluster members. We then use photometric redshifts and colour selection
to separate background galaxies from potential cluster members and test the
reliability of this technique using archival observations of submillimetre
galaxies. We find two potential MS 0451-03 members, which, if they are both
cluster galaxies have a total star-formation rate (SFR) of ~100 solar masses
per year -- a significant fraction of the combined SFR of all the other
galaxies in MS 0451-03. We also examine the stacked rest-frame mid-infrared,
millimetre and radio emission of cluster members below our AzTEC detection
limit and find that the SFRs of mid-IR selected galaxies in the cluster and
redshift-matched field populations are comparable. In contrast, the average SFR
of the morphologically classified late-type cluster population is ~3 times less
than the corresponding redshift-matched field galaxies. This suggests that
these galaxies may be in the process of being transformed on the red-sequence
by the cluster environment. Our survey demonstrates that although the
environment of MS 0451-03 appears to suppress star-formation in late-type
galaxies, it can support active, dust-obscured mid-IR galaxies and potentially
millimetre-detected LIRGs.
