GaLactic and Extragalactic All-sky Murchison Widefield Array survey eXtended (GLEAM-X) I: Survey description and initial data release. (23rd August 2022)

• Record Type: Journal Article
• Authors: Hurley-Walker, N.; Galvin, T. J.; Duchesne, S. W.; Zhang, X.; Morgan, J.; Hancock, P. J.; An, T.; Franzen, T. M. O.; Heald, G.; Ross, K.; Vernstrom, T.; Anderson, G. E.; Gaensler, B. M.; Johnston-Hollitt, M.; Kaplan, D. L.; Riseley, C. J.; Tingay, S. J.; Walker, M.
• Is Part Of: Publications of the Astronomical Society of Australia. Volume 39(2022)
• Publication Date: 2022-08-23
• Subjects: techniques: interferometric -- galaxies: general -- radio continuum: surveys; Astronomy -- Periodicals; Southern sky (Astronomy) -- Periodicals; Astrophysics -- Periodicals; Periodicals; 520.5
• DOI: 10.1017/pasa.2022.17
• Languages: English
• ISSNs: 1323-3580

Abstract

Abstract: We describe a new low-frequency wideband radio survey of the southern sky. Observations covering 72–231 MHz and Declinations south of $+30^\circ$ have been performed with the Murchison Widefield Array "extended" Phase II configuration over 2018–2020 and will be processed to form data products including continuum and polarisation images and mosaics, multi-frequency catalogues, transient search data, and ionospheric measurements. From a pilot field described in this work, we publish an initial data release covering 1, 447 $\mathrm{deg}^2$ over $4\, \mathrm{h}\leq \mathrm{RA}\leq 13\, \mathrm{h}$, $-32.7^\circ \leq \mathrm{Dec} \leq -20.7^\circ$ . We process twenty frequency bands sampling 72–231 MHz, with a resolution of 2′–45 ′′, and produce a wideband source-finding image across 170–231 MHz with a root mean square noise of $1.27\pm0.15\, \mathrm{mJy\, beam}^{-1}$ . Source-finding yields 78, 967 components, of which 71, 320 are fitted spectrally. The catalogue has a completeness of 98% at ${{\sim}}50\, \mathrm{mJy}$, and a reliability of 98.2% at $5\sigma$ rising to 99.7% at $7\sigma$ . A catalogue is available from Vizier; images are made available via the PASA datastore, AAO Data Central, and SkyView. This is the first in a series of data releases from the GLEAM-X survey.