Evolutionary map of the universe : large-n astronomy

EMU is an all-sky radio survey, and one of the two key projects primarily driving the design and construction of the new Australian SKA Pathfinder (ASKAP). EMU represents an enormous leap in the global radio-Astronomy capability, increasing the total number of known radio sources to about 70 million, from the 2.5 million detected over the entire previous history of radio-Astronomy. Next-generation radio continuum surveys such as EMU break through a sensitivity threshold such that they will be equally dominated by star formation and Active Galactic Nuclei (AGN), whereas earlier radio continuum surveys were completely dominated by AGN. The impact is even higher because the millions of sources enable fine-grained statistical studies: The large numbers enable the sample to be chopped up along many different orthogonal axes, so even subtle correlations can be detected. EMU will also almost certainly discover unexpected phenomena. While the first ASKAP observations, using prototype receivers, have already been published, the first deep observations (ASKAP early science) are expected to start in 2016, and we hope the full survey will start about a year after that. A key feature of EMU is that, as well as its key science goals, it is being designed to search for unexpected discoveries.