The Widefield ASKAP L-band Legacy All-sky Blind surveY (WALLABY)[1][2][3] is a next-generation survey of the 21 cm radio emission from neutral hydrogen (HI) in the Local Universe. It is hosted by the Australian Square Kilometer Array Pathfinder (ASKAP) telescope, WALLABY will survey three-quarters of the sky over a Declination range −90° to +30° to a redshift of 0.26. It will have a angular resolution of 30 arcsec and a sensitivity of 1.6 mJy/beam in each 4 km/s channel. WALLABY is expected to detect about 500,000 galaxies with a mean redshift of 0.05, at a mean distance of about 200 Mpc. The scientific goals of WALLABY include:

  • a census of gas-rich galaxies in the vicinity of the Local Group;
  • a study of the HI properties of galaxies, groups and clusters, including the influence of the environment on galaxy evolution;

History

The WALLABY project was proposed in 2009 by a team led by B. S. Koribalski and L. Staveley-Smith. It was ranked by ASKAP in the top two of ten Survey Science projects, with Koribalski and Staveley-Smith the principal investigators. Koribalski stepped down in 2019. Currently, Lister Staveley-Smith is the Principal Investigator, Karen Lee-Waddell is the project scientist, and Tobias Westmeier is the project manager.. The WALLABY team now has over 150 members.[4]

Early science results

Several science results have been published from WALLABY Early Science observations. Highlights include three observations of groups of galaxies,[5][6][7] and two detailed studies of nearby galaxies.[8][9]

WALLABY pilot survey

In preparation for the full WALLABY survey, expected to start in 2021, WALLABY conducted a pilot survey in 2020, consisting of three survey fields in the direction of Hydra, NGC 4636 and Norma. All data have been fully observed, and the Hydra field has been calibrated and imaged, leading to the first internal release of data for almost 150 HI detections in the direction of the Hydra cluster. WALLABY science teams are currently analysing the Hydra data, and first science papers are expected in late 2020.

References

  1. ↑ Schinckel, Antony; Bock, Douglas (16 January 2017). "The Australian Square Kilometre Array Pathfinder finally hits the big-data highway". The Conversation. Retrieved 2020-10-12.
  2. ↑ Koribalski, Bärbel S.; Staveley-Smith, L.; Westmeier, T.; Serra, P.; Spekkens, K.; Wong, O. I.; Lee-Waddell, K.; Lagos, C. D. P.; Obreschkow, D.; Ryan-Weber, E. V.; Zwaan, M. (2020-07-13). "WALLABY – an SKA Pathfinder H i survey". Astrophysics and Space Science. 365 (7): 118. arXiv:2002.07311. Bibcode:2020Ap&SS.365..118K. doi:10.1007/s10509-020-03831-4. ISSN 1572-946X. S2CID 211146706.
  3. ↑ "WALLABY Survey – WALLABY Survey Site". Retrieved 2020-10-12.
  4. ↑ "Team – WALLABY Survey". Retrieved 2020-10-12.
  5. ↑ For, B.-Q.; Staveley-Smith, L.; Westmeier, T.; Whiting, M.; Oh, S.-H.; Koribalski, B.; Wang, J.; Wong, O. I.; Bekiaris, G.; Cortese, L.; Elagali, A. (2019-11-11). "WALLABY early science − V. ASKAP H i imaging of the Lyon Group of Galaxies 351". Monthly Notices of the Royal Astronomical Society. 489 (4): 5723–5741. doi:10.1093/mnras/stz2501. hdl:1885/266365. ISSN 0035-8711.
  6. ↑ Lee-Waddell, K.; Koribalski, B. S.; Westmeier, T.; Elagali, A.; For, B.-Q.; Kleiner, D.; Madrid, J. P.; Popping, A.; Reynolds, T. N.; Rhee, J.; Serra, P. (2019-08-21). "WALLABY Early Science – II. The NGC 7232 galaxy group". Monthly Notices of the Royal Astronomical Society. 487 (4): 5248–5262. arXiv:1901.00241. doi:10.1093/mnras/stz017. ISSN 0035-8711.
  7. ↑ Reynolds, T. N.; Westmeier, T.; Staveley-Smith, L.; Elagali, A.; For, B.-Q.; Kleiner, D.; Koribalski, B. S.; Lee-Waddell, K.; Madrid, J. P.; Popping, A.; Rhee, J. (2019-01-21). "WALLABY early science – I. The NGC 7162 galaxy group". Monthly Notices of the Royal Astronomical Society. 482 (3): 3591–3608. arXiv:1810.12466. doi:10.1093/mnras/sty2930. ISSN 0035-8711.
  8. ↑ Kleiner, D.; Koribalski, B. S.; Serra, P.; Whiting, M. T.; Westmeier, T.; Wong, O. I.; Kamphuis, P.; Popping, A.; Bekiaris, G.; Elagali, A.; For, B.-Q. (2019-10-01). "WALLABY Early Science – IV. ASKAP H i imaging of the nearby galaxy IC 5201". Monthly Notices of the Royal Astronomical Society. 488 (4): 5352–5369. arXiv:1907.12556. doi:10.1093/mnras/stz2063. ISSN 0035-8711.
  9. ↑ Elagali, A.; Staveley-Smith, L.; Rhee, J.; Wong, O. I.; Bosma, A.; Westmeier, T.; Koribalski, B. S.; Heald, G.; For, B.-Q.; Kleiner, D.; Lee-Waddell, K. (2019-08-01). "WALLABY early science – III. An H i study of the spiral galaxy NGC 1566". Monthly Notices of the Royal Astronomical Society. 487 (2): 2797–2817. arXiv:1905.09491. doi:10.1093/mnras/stz1448. ISSN 0035-8711.
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