Evolutionary Map of the Universe : tracing clusters to high red-shift

The Australian SKA Pathfinder (ASKAP) is a new radio-telescope being built in Western Australia. One of the key surveys for which it is being built is EMU (Evolutionary Map of the Universe), which will make a deep (~10 μJy/bm rms) radio continuum survey covering the entire sky as far North as +30°. EMU may be compared to the NRAO VLA Sky Survey (NVSS), except that it will have about 45 times the sensitivity, and five times the resolution. EMU will also have much better sensitivity to diffuse emission than previous large surveys, and is expected to produce a large catalogue of relics, tailed galaxies, and halos, and will increase the number of known clusters by a significant factor. Here we describe the EMU project and its impact on the astrophysics of clusters.