Radio study of X-ray clusters of galaxies - II. A1300: a post-merger cluster at z=0.31 containing a halo and a relic

As part of an extensive radio-IR-optical-X-ray study of ROSAT clusters of g alaxies in the Hydra region we have observed the Abell cluster A1300, one o f the most distant (z similar or equal to 0.31) and X-ray luminous (L-X sim ilar to 1.7 x 10(45) erg s(-1) cm(-2), 0.1-2.4 keV) clusters in the sample, with the Molonglo Observatory Synthesis Telescope at 843 MHz and the Austr alia Telescope Compact Array at 1.34, 2.4, 4.8 and 8.6 GHz. Previous results in the X-ray and optical have suggested that A1300 is in a post-merging phase. We present further evidence of this with the discovery of two diffuse radio sources projected within the extended X-ray emission of A1300. These may be among the most distant radio halo and relic sources yet found. We argue that the halo source, which is seen in projection near the centre of the cluster and coincides with an extension in the X-ray surf ace brightness distribution, is the result of a cluster-wide process relate d to the merger.