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

• DOI: 10.1017/pasa.2022.17
• Publication Date: 2022-08-23T05:00:25Z
• Authors: N. Hurley-Walker; T. J. Galvin; S. W. Duchesne; X. Zhang; J. Morgan; P. J. Hancock; T. An; T. M. O. Franzen; G. Heald; K. Ross; T. Vernstrom; G. E. Anderson; B. M. Gaensler; M. Johnston-Hollitt; D. L. Kaplan; C. J. Riseley; S. J. Tingay; M. Walker
• Keywords: FOS: Physical sciences; Astrophysics - Astrophysics of Galaxies; 01 natural sciences; 520; interferometric – galaxies; surveys; 13. Climate action; Astrophysics of Galaxies (astro-ph.GA); 0103 physical sciences; general – radio continuum; techniques; Astrophysics - Instrumentation and Methods for Astrophysics; Instrumentation and Methods for Astrophysics (astro-ph.IM)

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.