A radio survey of seven southern X-ray luminous clusters of galaxies

Abstract

The Australia Telescope Compact Array (ATCA) has been used at 1.38 and 2.38 GHz to survey seven southern Abell clusters of galaxies with high X-ray luminosities: A2746, A2837, A3126, A3216, A3230, A3827 and A3836. The clusters have also been surveyed at 0.843 GHz with the Molonglo Observatory Synthesis Telescope (MOST). We have listed a complete 1.38-GHz sample of 149 radio sources within the Abell circles centred on their X-ray centroids. We compare their identification fractions, emitted 1.38 GHz and optical powers, radio spectral indices and radial variation in projected source density with those of the radio-selected samples of Slee, Roy & Andernach. We compare our fractional radio luminosity function with that of the radio-selected samples of Ledlow & Owen and Slee et al. Three significant differences are noted between X-ray and radio-selected samples of clusters: (1) the X-ray sample has an excess of flat-spectrum radio sources; (2) the fractional radio luminosity function for the Fanaroff-Riley I (FR I) sources in the X-ray selected sample is much steeper, implying that fewer of their cluster galaxies become hosts for the stronger FR I radio galaxies; (3) a complete absence of Fanaroff-Riley II (FR II) radio galaxies in the X-ray selected sample. The average excess projected density of radio sources near our cluster centres is ∼five times the background source density. © 2008 Royal Astronomical Society.