The Australia Telescope Large Area Survey: Spectroscopic Catalogue and
  Radio Luminosity Functions
  The Australia Telescope Large Area Survey (ATLAS) has surveyed seven square
degrees of sky around the Chandra Deep Field South (CDFS) and the European
Large Area ISO Survey - South 1 (ELAIS-S1) fields at 1.4 GHz. ATLAS aims to
reach a uniform sensitivity of $10 \mu$Jy beam$^{-1}$ rms over the entire
region with data release 1 currently reaching $\sim30 \mu$Jy beam$^{-1}$ rms.
Here we present 466 new spectroscopic redshifts for radio sources in ATLAS as
part of our optical follow-up program. Of the 466 radio sources with new
spectroscopic redshifts, 142 have star-forming optical spectra, 282 show
evidence for AGN in their optical spectra, 10 have stellar spectra and 32 have
spectra revealing redshifts, but with insufficient features to classify. We
compare our spectroscopic classifications with two mid-infrared diagnostics and
find them to be in broad agreement. We also construct the radio luminosity
function for star-forming galaxies to z $= 0.5$ and for AGN to z $= 0.8$. The
radio luminosity function for star-forming galaxies appears to be in good
agreement with previous studies. The radio luminosity function for AGN appears
higher than previous studies of the local AGN radio luminosity function. We
explore the possibility of evolution, cosmic variance and classification
techniques affecting the AGN radio luminosity function. ATLAS is a pathfinder
for the forthcoming EMU survey and the data presented in this paper will be
used to guide EMU's survey design and early science papers.
