An AzTEC 1.1 mm survey of the GOODS-N field -- II. Multi-wavelength
  identifications and redshift distribution
  We present results from a multi-wavelength study of 29 sources (false
detection probabilities <5%) from a survey of the Great Observatories Origins
Deep Survey-North field at 1.1mm using the AzTEC camera. Comparing with
existing 850um SCUBA studies in the field, we examine differences in the source
populations selected at the two wavelengths. The AzTEC observations uniformly
cover the entire survey field to a 1-sigma depth of ~1mJy. Searching deep
1.4GHz VLA, and Spitzer 3--24um catalogues, we identify robust counterparts for
21 1.1mm sources, and tentative associations for the remaining objects. The
redshift distribution of AzTEC sources is inferred from available spectroscopic
and photometric redshifts. We find a median redshift of z=2.7, somewhat higher
than z=2.0 for 850um-selected sources in the same field, and our lowest
redshift identification lies at a spectroscopic redshift z=1.1460. We measure
the 850um to 1.1mm colour of our sources and do not find evidence for `850um
dropouts', which can be explained by the low-SNR of the observations. We also
combine these observed colours with spectroscopic redshifts to derive the range
of dust temperatures T, and dust emissivity indices $\beta$ for the sample,
concluding that existing estimates T~30K and $\beta$~1.75 are consistent with
these new data.
