The positions, structures, and polarizations of 404 compact radio sources

Accurate positions of 404 compact radio sources used as calibrators by the VLA are presented. In addition, the structure and polarization of each source at both 4885 and 1465 MHz are given. Eighty-five percent of the sources have spectral indices flatter than 0.5; all of these are dominated by an unresolved core. Half of these flat-spectrum sources contain nearby, associated diffuse structure at a level exceeding approximately 0.4% of the core brightness at 20 cm.