GaLactic and Extragalactic All-sky Murchison Widefield Array survey eXtended (GLEAM-X) I: Survey Description and Initial Data Release

TL;DR

The GLEAM-X survey provides a comprehensive low-frequency radio sky map of the southern hemisphere, with detailed source catalogues and initial data release covering 1,447 square degrees, enhancing our understanding of radio sources at these frequencies.

Contribution

This paper introduces the GLEAM-X survey, a new wideband low-frequency radio survey with initial data release, covering a large sky area with high sensitivity and detailed source catalogues.

Findings

Produced a source catalogue with nearly 79,000 components.

Achieved 98% completeness at 50 mJy flux density.

Provided high-quality images and data products for the southern sky.

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 sq. deg over 4h < RA < 13h, -32.7deg < Dec < -20.7deg. We process twenty frequency bands sampling 72 - 231 MHz, with a resolution of $2'$ - $45"$, and produce a wideband source-finding image across 170 - 231MHz with a root-mean-square noise of $1.27\pm0.15$ mJy/beam. Source-finding yields 78,967 components, of which 71,320 are fitted spectrally. The catalogue has a completeness of 98% at $\sim50$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 on AAO Data Central, SkyView, and the PASA Datastore. This is the first in a series of data releases from the GLEAM-X survey.