The Parkes Selected Regions: deep optical and infrared observations of radio galaxies and quasars at high redshifts

Abstract

We report the results of an extensive optical and infrared study of the 178 radio sources in the Parkes Selected Regions (S > 100 mJy at 2.7 GHz). CCD observations have resulted in the essential completion (≳ 95 per cent) of the optical identification programme, and have provided B and R photometry of the new identifications. In addition, K photometry has been completed for four of the six Selected Regions. New spectroscopic observations have increased the redshift content to 46 per cent, including virtually all the quasar candidates. We discuss redshift estimation for the remaining radio galaxies in the light of the B, R and K photometry; it appears unlikely that more than 10 objects out of the total of 178 can lie at z > 2.5.