A 5-GHz Southern Hemishere VLBI Survey of Compact Radio Sources.I.

Abstract

We report the results of a 5-GHz southern hemisphere VLBI survey of compact extragalactic radio sources. These observations were undertaken with the SHEVE array plus Shanghai station in 1992 November. A sample of 22 sources was observed and images of 20 of them were obtained. Of the 20 sources imaged, 15 showed core-jet structure, 1 had a two-sided jet, and 4 had only single compact cores. Eleven of the 16 core-jet (including one two-sided jet) sources showed some evidence of bent jets. No compact doubles were found. A comparison with previous images and the temporal variability of the radio flux density showed evidence for superluminal motion in four of the sources. Five sources were high-energy (>100 MeV) γ-ray sources. Statistical analysis showed the dominance of highly polarized quasars among the detected γ-ray sources, which emphasizes the importance of beaming effect in the γ-ray emission.