Complete identification of the Parkes half-Jansky sample of GHz peaked spectrum radio galaxies ^*,**

¹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA, Leiden, The Netherlands e-mail: vriesn@strw.leidenuniv.nl
² International Square Kilometre Array Project office, Postbus 2, 7990 AA, Dwingeloo, The Netherlands
³ Max-Planck-Institut für extraterrestrische Physik (MPE), Postfach 1312, 85741 Garching, Germany
⁴ Laboratoire d'Études des Galaxies, Étoiles, Physique et Instrumentation, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
⁵ Department of Physics, Bristol University, H H Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UK

Received: 4 October 2006
Accepted: 15 December 2006

Abstract

Context.Gigahertz Peaked Spectrum (GPS) radio galaxies are generally thought to be the young counterparts of classical extended radio sources. Statistically complete samples of GPS sources are vital for studying the early evolution of radio-loud AGN and the trigger of their nuclear activity. The “Parkes half-Jansky” sample of GPS radio galaxies is such a sample, representing the southern counterpart of the 1998 Stanghellini sample of bright GPS sources.

Aims.As a first step of the investigation of the sample, the host galaxies need to be identified and their redshifts determined.

Methods.Deep R-band VLT-FORS1 and ESO 3.6 m EFOSC II images and long slit spectra have been taken for the unidentified sources in the sample.

Results.We have identified all twelve previously unknown host galaxies of the radio sources in the sample. Eleven have host galaxies in the range , while one object, PKS J0210+0419, is identified in the near infrared with a galaxy with . The redshifts of 21 host galaxies have been determined in the range , bringing the total number of redshifts to 39 (80%). Analysis of the absolute magnitudes of the GPS host galaxies show that at they are on average a magnitude fainter than classical 3C radio galaxies, as found in earlier studies. However their restframe UV luminosities indicate that there is an extra light contribution from the AGN, or from a population of young stars.