Bright radio sources at 178 MHz: flux densities, optical identifications and the cosmological evolution of powerful radio galaxies

Abstract

In order to correct the biases introduced into the 3CR catalogue by confusion and partial resolution, a revised sample of bright sources has been defined at 178 MHz. The sample is 96 per cent complete to a flux-density limit of 10 Jy for sources smaller than 10 arcmin. The incompleteness of 3CR to sources of larger angular size has also been reduced. 96 per cent of the sources in the revised sample are identified optically, 71 and 25 per cent with galaxies and quasars, respectively. The radio-galaxy population shows strong space-density evolution for luminosities in excess of ~ 10 26 * 5 W Hz -1 sr -1 at 178 MHz (redshifts ^ 0.2); the evolutionary properties of galaxies and quasars of the same luminosity and redshift are very similar.