The Molonglo Southern 4 Jy sample (MS4). II. ATCA imaging and optical identification

Of the 228 sources in the Molonglo Southern 4 Jy Sample (MS4), the 133 with angular sizes < 35 arcsec have been imaged at 5 GHz at 2-4 arcsec resolution with the Australia Telescope Compact Array. More than 90% of the sample has been reliably optically identified, either on the plates of the UK Schmidt Southern Sky Survey or on R-band CCD images made with the Anglo-Australian Telescope. A subsample of 137 sources, the SMS4, defined to be a close southern equivalent of the northern 3CRR sample, was found to have global properties mostly consistent with the northern sample. Linear sizes of MS4 galaxies and quasars were found to be consistent with galaxy-quasar unification models of orientation and evolution.