WALLABY – an SKA Pathfinder H I survey

Bärbel S. Koribalski*, L. Staveley-Smith, T. Westmeier, P. Serra, K. Spekkens, O. I. Wong, K. Lee-Waddell, C. D. P. Lagos, D. Obreschkow, E. V. Ryan-Weber, M. Zwaan, V. Kilborn, G. Bekiaris, K. Bekki, F. Bigiel, A. Boselli, A. Bosma, B. Catinella, G. Chauhan, M. E. CluverM. Colless, H. M. Courtois, R. A. Crain, W. J. G. de Blok, H. Dénes, A. R. Duffy, A. Elagali, C. J. Fluke, B. Q. For, G. Heald, P. A. Henning, K. M. Hess, B. W. Holwerda, C. Howlett, T. Jarrett, D. H. Jones, M. G. Jones, G. I. G. Józsa, R. Jurek, E. Jütte, P. Kamphuis, I. Karachentsev, J. Kerp, D. Kleiner, R. C. Kraan-Korteweg, Á. R. López-Sánchez, J. Madrid, M. Meyer, J. Mould, C. Murugeshan, R. P. Norris, S. H. Oh, T. A. Oosterloo, A. Popping, M. Putman, T. N. Reynolds, J. Rhee, A. S. G. Robotham, S. Ryder, A. C. Schröder, Li Shao, A. R. H. Stevens, E. N. Taylor, J. M. van der Hulst, L. Verdes-Montenegro, B. P. Wakker, J. Wang, M. Whiting, B. Winkel, C. Wolf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

57 Citations (Scopus)


The Widefield ASKAP L-band Legacy All-sky Blind surveY (wallaby) is a next-generation survey of neutral hydrogen (H I) in the Local Universe. It uses the widefield, high-resolution capability of the Australian Square Kilometer Array Pathfinder (ASKAP), a radio interferometer consisting of 36 × 12-m dishes equipped with Phased-Array Feeds (PAFs), located in an extremely radio-quiet zone in Western Australia. wallaby aims to survey three-quarters of the sky (− 90 < δ< + 30 ) to a redshift of z≲ 0.26 , and generate spectral line image cubes at ∼30 arcsec resolution and ∼1.6 mJy beam−1 per 4 km s−1 channel sensitivity. ASKAP’s instantaneous field of view at 1.4 GHz, delivered by the PAF’s 36 beams, is about 30 sq deg. At an integrated signal-to-noise ratio of five, wallaby is expected to detect around half a million galaxies with a mean redshift of z∼ 0.05 (∼200 Mpc). The scientific goals of wallaby include: (a) a census of gas-rich galaxies in the vicinity of the Local Group; (b) a study of the H I properties of galaxies, groups and clusters, in particular the influence of the environment on galaxy evolution; and (c) the refinement of cosmological parameters using the spatial and redshift distribution of low-bias gas-rich galaxies. For context we provide an overview of recent and planned large-scale H I surveys. Combined with existing and new multi-wavelength sky surveys, wallaby will enable an exciting new generation of panchromatic studies of the Local Universe. — First results from the wallaby pilot survey are revealed, with initial data products publicly available in the CSIRO ASKAP Science Data Archive (CASDA).

Original languageEnglish
Article number118
Pages (from-to)1-35
Number of pages35
JournalAstrophysics and Space Science
Issue number7
Publication statusPublished - 13 Jul 2020


  • ISM – large-scale structure
  • ISM – surveys – galaxies: evolution, formation, kinematics & dynamics
  • Radio lines: galaxies


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