GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I : A low-frequency extragalactic catalogue
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Author
Hurley-Walker, Natasha
Callingham, Joseph R.
Hancock, Paul J.
Franzen, Thomas M. O.
Hindson, Luke
Kapinska, Anna D.
Morgan, John
Offringa, Andre R.
Wayth, Randall B.
Wu, Chen
Zheng, Q.
Murphy, Tara
Bell, Martin E.
Dwarakanath, K. S.
For, Bi-Qing
Gaensler, Bryan M.
Johnston-Hollitt, Melanie
Lenc, Emil
Procopio, Pietro
Staveley-Smith, Lister
Ekers, Ron
Bowman, Judd D.
Briggs, Frank
Cappallo, R. J.
Deshpande, Avinash A.
Greenhill, Lincoln
Hazelton, Brynah J.
Kaplan, David L.
Lonsdale, Colin J.
McWhirter, S. R.
Mitchell, Daniel A.
Morales, Miguel F.
Morgan, Edward
Oberoi, Divya
Ord, Stephen M.
Prabu, T.
Shankar, N. Udaya
Srivani, K. S.
Subrahmanyan, Ravi
Tingay, Steven J.
Webster, Rachel L.
Williams, Andrew
Williams, Christopher L.
Attention
2299/17654
Abstract
Using the Murchison Widefield Array (MWA), the low-frequency Square Kilometre Array (SKA1 LOW) precursor located in Western Australia, we have completed the GaLactic and Extragalactic All-sky MWA (GLEAM) survey, and present the resulting extragalactic catalogue, utilising the first year of observations. The catalogue covers 24,831 square degrees, over declinations south of $+30^\circ$ and Galactic latitudes outside $10^\circ$ of the Galactic plane, excluding some areas such as the Magellanic Clouds. It contains 307,455 radio sources with 20 separate flux density measurements across 72--231MHz, selected from a time- and frequency- integrated image centred at 200MHz, with a resolution of $\approx 2$'. Over the catalogued region, we estimate that the catalogue is 90% complete at 170mJy, and 50% complete at 55mJy, and large areas are complete at even lower flux density levels. Its reliability is 99.97% above the detection threshold of $5\sigma$, which itself is typically 50mJy. These observations constitute the widest fractional bandwidth and largest sky area survey at radio frequencies to date, and calibrate the low frequency flux density scale of the southern sky to better than 10%. This paper presents details of the flagging, imaging, mosaicking, and source extraction/characterisation, as well as estimates of the completeness and reliability. All source measurements and images are available online (http://www.mwatelescope.org/science/gleam-survey). This is the first in a series of publications describing the GLEAM survey results.