  The Australia Telescope Large Area Survey (ATLAS) is the widest deep radio
survey ever attempted, covering 7 square degrees of sky in two separate fields,
with extensive multi-wavelength data. The primary aim of this research is to
investigate all possible discriminants between active galactic nuclei (AGN) and
star-formation (SF) in ATLAS, with the goal of comparing discriminants,
identifying the strengths and weaknesses, and establishing an optimum technique
given the available data. Ultimately, all possible discriminants will be
utilized, including optical/infrared SEDs, spectroscopic line widths, optical
line ratios, radio spectral indices, variability, morphology, polarization and
the radio/FIR correlation. A preliminary investigation using only the available
spectroscopic data in ATLAS is ongoing. Results from this investigation are
presented, exploring the proportion of AGN/SF galaxies as a function of radio
flux density down to 150 microJy. Three faint GPS candidates are also
presented, as a preliminary result from ATLAS.
