The K‐z diagram of FIRST radio sources identified in the Boötes and Cetus fields

Abstract

AbstractThis paper presents the Hubble diagram (K‐z relation) for FIRST (Faint Images of the Radio Sky at 20 cm) radio sources identified in the Boötes and Cetus fields. The correlation between the K magnitude of the FIRST‐NDWFS sample and the photometric redshifts found to be linear. The dispersion about the best fit line is given by 1.53 for the whole sample and 0.75 at z > 1. The paper also presents a composite K‐z diagram of FIRST radio sources and low‐frequency selected radio samples with progressively fainter flux‐density limits (3CRR, 6C, 7CRS and the EIS‐NVSS sample). The majority of FIRST radio sources lie fainter than the no evolution curve (3 L* galaxies) probably highlighting the fact that the galaxy luminosity is correlated with the radio power (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)