Deep, wide-field radio imaging
Our view of the high-redshift universe was transformed by the UK ATC's SCUBA instrument which discovered a previously unknown population of galaxies undergoing intense star formation. Due to SCUBA's (and other bolometer arrays') relatively coarse angular resolution, identifying the counterparts to these sources at other wavelengths has relied upon deep radio interferometric imaging, with a beam which is typically smaller than SCUBA's by a factor of ten. The technique works because the radio and FIR luminosities of a star-forming galaxy are extremely well correlated and the radio sky much less crowded. The radio field of view is also very large, enabling large areas (quarter of a square degree) to be imaged instantaneously. At the UK ATC we are involved in a number of programs to use the VLA, MERLIN and the GMRT to first identify and then investigate these sources in detail e.g. their morphologies, emission mechanisms and spectral indices. Also detected in these images are radio galaxies and Active Galactic Nuclei, sources which are also the subject of current research at the UK ATC. The image shows the central area of the Hubble Deep Field North, observed at 1.4 GHz with the VLA. (Contacts: Rob Ivison)