The Fleurs Southern Benchmark Program

A program to determine accurate radio positions and optical identifications of southern flat-spectrum radio sources has been undertaken with the six-dish array of the Fleurs synthesis telescope at 1.4 GHz and using the SERC J sky survey. This sample covers the declination range -80 deg to -50 deg and comprises all 198 sources from the Parkes catalogue with α of > -0.5 and flux density of 0.25 Jy. The radio astrometric phase of the program is complete. It is concluded that by comparison with accurate VLBI positions the FST positions have r.m.s. uncertainties of ∼0 seconds .9. There is no global bias in the FST positions at the 0 seconds .2 to 0 seconds .3 level relative to the JPL VLBI extragalactic reference frame. A comparison with positions from the Parkes catalogue shows that in the southern regions the Parkes catalogue has rms position errors of about 9 seconds. There is no significant bias between the FST and Parkes positions. 16 refs., figs