GLEAM-300: The GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey at 300 MHz

Abstract

In this paper we present a wide-field radio survey at 300 MHz covering the sky from $-90^{\circ }\le \hat{I}{´}_{\text{J2000}}\lesssim +40^{\circ }$ using the Murchison Widefield Array (MWA). This 300-MHz survey follows the Galactic and Extragalactic All-sky MWA (GLEAM) survey, and provides an additional comparatively high-frequency data point to existing multi-frequency (72-231 MHz) data. With this data release we provide mosaic images and a catalogue of compact source components. We use two-minute snapshot observations covering 2015-2016, combining overlapping two-minute snapshot images to provide full-sensitivity mosaic images with a median root-mean-square noise of $9.1_{-2.8}^{+5.5}$ mJy beam${}^{-1}$ and median angular resolution of $128.8^{\prime \prime }\times 112.5^{\prime \prime }$, with some position-dependent variation. We find a total of 338 080 unique Gaussian components across the mosaic images. The survey is the first at 300 MHz from the MWA covering the whole Southern Hemisphere. It provides a unique spectral data point that complements the existing GLEAM survey and the ongoing GLEAM-eXtended survey, and points toward results from the upcoming SKA-Low surveys.

30 pages, 58 figure files. Accepted for publication in PASA. The catalogue and images are available at https://doi.org/10.25919/z80f-5t62