The cosmological evolution of radio galaxies with CENSORS

Abstract

Abstract. The Combined EIS-NVSS Survey Of Radio Sources (CENSORS) has been developed, over the last four years, with the primary goal of investigating the cosmological evolution of the radio luminosity function. This 1.4 GHz sample, complete to the 7.2mJy level, contains 150 radio sources. Host galaxies are now 92% identified in optical and near-IR bands and the sample is now 60% spectroscopically complete, with estimated redshifts available for the remainder via the K-z relation for radio galaxies. In conjunction with other radio selected samples, covering a wide range in redshift and radio luminosities, the CENSORS survey has been used to investigate the behaviour of the comoving density of radio sources as a function of redshift and radio luminosity. Preliminary results indicate that the data now available will be able to detect a redshift cut-off for sources of 1.4 GHz radio luminosity ∼ 10 27 W Hz −1 . A V /Vmax test indicates negative evolution at redshifts greater than 2.5.