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

Abstract

We present the results of an approximately 6,100 deg[superscript 2] 104-196 MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December: the 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 < RA < 8.5 h, -58° < Dec < -14°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 [superscript -1], with reduced sensitivity near the field boundaries and bright sources. We describe the data reduction strategy, based upon mosaicked 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. Keywords: surveys; radio continuum; general - surveys - techniques; interferometric