Parkes Half-Jansky Flat-Spectrum Sample

The sample contains 323 sources selected according to a flux limit of 0.5 Jy at 2.7 GHz, a spectral index measured between 2.7 and 5.0 GHz of {alpha}(2.7/5.0) > -0.5, where S(f) is proportional to f^alpha^, Galactic latitude |b| > 20{deg} and -45{deg} < Declination(B1950) < +10{deg}.

The sample was selected from a region 3.90 steradians in area. We have obtained accurate radio positions for all the unresolved sources in this sample and combined these with accurate optical positions from digitised photographic sky survey data to check all the optical identifications. We report new identifications based on R- and Kn-band imaging and new spectroscopic measurements of many of the sources.