Structures, spectral indexes, and optical identifications of radio sources selected from the B3 catalogue

A homogeneous sample of 1103 radio sources which were selected from the Third Bologna Catalogue (Ficarra et al., 1985) at 408 MHz and which cover the flux-density range from 2.0-1.0 Jy has been mapped at 1465 MHz using the VLA at 15 arcsec resolution. Identifications are proposed for 354 of the sources. The results suggest that sizable intrinsic radio-optical displacements are possible for steep-spectrum unresolved sources, that the 408-1465 MHz spectra become steeper with decreasing flux density (to about 50 mJy), and that metric size and redshift are negatively correlated for radio galaxies. (R.R.)