CAASTRO and WALLABY/DINGO
The Widefield ASKAP L-Band Legacy All-sky Blind SurveY (WALLABY) and the Deep Investigation of Neutral Gas Origins (DINGO) are two ASKAP surveys that together aim to detect around 700,000 galaxies in the 21cm line of neutral atomic hydrogen. The data from these projects will provide a comprehensive view of the mass-assembly history of the Universe.
WALLABY (PIs B. Koribalski and L. Staveley-Smith) is a precursor for future, much deeper SKA HI surveys. It will cover three-quarters of the sky to redshifts of z = 0.26 and a median redshift of 0.05. As an all-sky survey, it will form the basis for several CAASTRO projects across both the Evolving and Dark themes.
DINGO (PI M. Meyer) is also a precursor for future SKA HI surveys. DINGO will perform an ultra-deep survey of 60 deg2 of sky, a less deep survey of 150 deg2, and will be the first HI survey to examine evolution of HI properties of a large sample of galaxies to a significant redshift.
Simulations suggest that in the WALLABY and DINGO survey volumes, around 700,000 galaxies are detectable in the 21-cm line of neutral atomic hydrogen. We will measure the HI properties of each galaxy and derive its distance, HI mass, total mass and dark matter content. The 30 arcsec (possibly 10 arcsec) angular resolution of WALLABY will allow us to easily identify likely optical and/or infrared counterparts.
|The Australian Square Kilometre Array Pathfinder (ASKAP) telescope plays a critical role in the WALLABY and DINGO surveys.
ASKAP is optimised for fast HI surveys, and will be the most powerful radio telescope for this type of science until the SKA phase 1 is constructed (DINGO) or phase 2 is constructed (WALLABY). The detailed science aims of the WALLABY survey include: (1) galaxy formation and the missing satellite problem in the Local Group, (2) evolution and star-formation in galaxies, (3) mergers and interactions in galaxies, (3) the HI mass function and its variation with galaxy density, (4) physical processes governing the distribution and evolution of cool gas at low redshift, (5) cosmological parameters relating to gas-rich galaxies, and (6) the nature of the cosmic web. The detailed science aims of the DINGO survey include the evolution of the HI mass function, the 2pt correlation function and the halo occupation distribution function, and a study of the co-evolution of the stellar, baryonic, and dark matter content of galaxies over the past 4 Gyr.
The project leader for CAASTRO part of the WALLABY/DINGO projects is Professor Lister Staveley-Smith (University of Western Australia). CAASTRO's current and future contributions include: (1) the development of kinematic pipelines for velocity field analysis; (2) using halo mass functions and simulations to test CDM theory; (3) source catalogue reliability and completeness; (4) study of the HI mass function and environmental dependence; and (5) probing cosmic evolution using the techniques of stacking and intensity mapping. CAASTRO is also leading Tully-Fisher projects relating to WALLABY. WALLABY and DINGO are large projects involving over 100 scientists around the world.