Widefield ASKAP L-Band Legacy All-Sky Blind Survey

Principal Investigators: Lister Staveley-Smith and Barbara Catinella (ICRAR/University of Western Australia)

WALLABY is the ASKAP all-sky survey of neutral hydrogen (HI) in the Local Universe out to a redshift of z ~ 0.1. The survey will produce HI data cubes of the sky at an angular resolution of 30 arcsec and a spectral resolution of 18.5 kHz (~4 km/s). WALLABY will reach a sensitivity of 1.6 mJy (rms per beam and channel) and be able to detect the 21-cm HI emission of a few hundred thousand galaxies across the sky. In addition, WALLABY will produce high-resolution data cubes of several thousand selected galaxies across the sky at ~10 arcsec angular resolution. WALLABY will cover ~14,000 deg² of sky during the 5 years of ASKAP survey operations. The exact sky footprint is available from the WALLABY website.

The main scientific goals of WALLABY include: (a) measurements of the velocity fields and rotation curves of galaxies to resolve the long-standing cusp-core tension in ΛCDM theory and to allow the baryonic/dark matter mass dissections of unprecedentedly large samples; (b) a study of the individual and statistical properties of galaxies in and around groups and clusters to better understand galaxy evolution, including the relative roles of tidal and hydrodynamic forces; (c) the most accurate measurement of the HI mass and velocity functions and their variation with environment (local density); (d) the refinement of cosmological parameters and tests of GR and ΛCDM using the spatial and redshift distribution of gas-rich galaxies; (e) a study of the dynamics of high-velocity clouds near the Milky Way and their role in tracing accretion and outflows; and (f) a census of gas-rich galaxies in the vicinity of the Local Group in order to quantify the role of the early ionization field on low-mass galaxy formation.