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

TL;DR

The GLEAM-300 survey provides a comprehensive 300 MHz radio sky map from the MWA, enhancing multi-frequency data and aiding future SKA-Low studies with high-resolution, wide-field observations of the Southern Hemisphere.

Contribution

This paper introduces the first 300 MHz all-sky survey from the MWA, offering high-resolution, full-sky coverage that complements existing low-frequency surveys and supports future radio astronomy research.

Findings

338,080 unique Gaussian components detected

Median noise level of 9.1 mJy/beam

Full-sky mosaic images with detailed source catalogues

Abstract

In this paper we present a wide-field radio survey at 300 MHz covering the sky from $-90^\circ \leq \delta_\text{J2000} \lesssim +40^\circ$ 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.