The Murchison Widefield Array Commissioning Survey: A Low-Frequency Catalogue of 14,110 Compact Radio Sources over 6,100 Square Degrees

TL;DR

The paper presents a comprehensive low-frequency radio sky survey covering over 6,100 square degrees, cataloging more than 14,000 sources with detailed flux and spectral data, achieved during the Murchison Widefield Array's commissioning phase.

Contribution

It provides the first large-scale, low-frequency radio source catalog from the Murchison Widefield Array commissioning data, including detailed source measurements and a novel data reduction approach.

Findings

Catalog of 14,110 sources with flux and spectral index

Coverage of 6,100 square degrees at 104--196 MHz

Resolution of 3 arcmin with 40 mJy/beam sensitivity

Abstract

We present the results of an approximately 6,100 square degree 104--196MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December: the Murchison Widefield Array Commissioning Survey (MWACS). The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The survey covers approximately 20.5 h < Right Ascension (RA) < 8.5 h, -58 deg < Declination (Dec) < -14 deg over three frequency bands centred on 119, 150 and 180 MHz, with image resolutions of 6--3 arcmin. The catalogue has 3-arcmin angular resolution and a typical noise level of 40 mJy/beam, with reduced sensitivity near the field boundaries and bright sources. We describe the data reduction strategy, based upon mosaiced snapshots, flux density calibration and source-finding method. We present a catalogue of flux density and spectral index measurements for 14,110 sources, extracted from the mosaic, 1,247 of which are sub-components of complexes of sources.