The Widefield ASKAP L-band Legacy All-sky Blind surveY (or WALLABY) is one of two key surveys that are now running on the Australian SKA Pathfinder (ASKAP), which is an innovative imaging radio telescope located in an extremely radio quiet zone (the Murchison Radio-astronomy Observatory) in Western Australia. The aim of WALLABY is to use the powerful widefield phased-array technology of ASKAP to observe three-quarters of the whole sky in the 21-cm line of neutral hydrogen (or HI) at 30-arcsec resolution, thereby detecting and imaging the gas distribution in hundreds of thousands of external galaxies in the local Universe. This will allow astronomers to gain a much improved understanding of the processes involved in galaxy formation and evolution, and the role of stellar and black hole feedback, gas accretion and galaxy interactions in these processes. Current WALLABY Early Science observing is using the so-called ASKAP-12 array, a one-third subset of the eventual 36-antenna ASKAP, and has so-far covered four 30 square degree fields. Early Science is allowing the team to develop, deploy and commission its pipeline processing, data verification and post-processing algorithms, as well as measuring the properties of hundreds of galaxies, including their distance, neutral hydrogen mass, and total mass. Full WALLABY is expected to start in 2019.
The proposed observing parameters for WALLABY are contained in the following table. Actual parameters depend on scheduling details and observing allocations, but early indications are that these specifications will be achieved.