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dc.contributor.authorFranzen, Thomas
dc.contributor.authorJackson, Carole
dc.contributor.authorOffringa, A.
dc.contributor.authorEkers, Ronald
dc.contributor.authorWayth, Randall
dc.contributor.authorBernardi, G.
dc.contributor.authorBowman, J.
dc.contributor.authorBriggs, F.
dc.contributor.authorCappallo, R.
dc.contributor.authorDeshpande, A.
dc.contributor.authorGaensler, B.
dc.contributor.authorGreenhill, L.
dc.contributor.authorHazelton, B.
dc.contributor.authorJohnston-Hollitt, M.
dc.contributor.authorKaplan, D.
dc.contributor.authorLonsdale, C.
dc.contributor.authorMcWhirter, S.
dc.contributor.authorMitchell, D.
dc.contributor.authorMorales, M.
dc.contributor.authorMorgan, E.
dc.contributor.authorMorgan, J.
dc.contributor.authorOberoi, D.
dc.contributor.authorOrd, S.
dc.contributor.authorPrabu, T.
dc.contributor.authorSeymour, Nick
dc.contributor.authorShankar, N.
dc.contributor.authorSrivani, K.
dc.contributor.authorSubrahmanyan, R.
dc.contributor.authorTingay, Steven
dc.contributor.authorTrott, Cathryn
dc.contributor.authorWebster, R.
dc.contributor.authorWilliams, Andrew
dc.contributor.authorWilliams, C.
dc.identifier.citationFranzen, T. and Jackson, C. and Offringa, A. and Ekers, R. and Wayth, R. and Bernardi, G. and Bowman, J. et al. 2016. The 154 MHz radio sky observed by the Murchison Widefield Array: Noise, confusion, and first source count analyses. Monthly Notices of the Royal Astronomical Society. 459 (3): pp. 3314-3325.

© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. We analyse a 154 MHz image made from a 12 h observation with the Murchison Widefield Array (MWA) to determine the noise contribution and behaviour of the source counts down to 30 mJy. The MWA image has a bandwidth of 30.72 MHz, a field-of-view within the half-power contour of the primary beam of 570 deg2, a resolution of 2.3 arcmin and contains 13 458 sources above 5s. The rms noise in the centre of the image is 4-5 mJy beam-1. The MWA counts are in excellent agreement with counts from other instruments and are the most precise ever derived in the flux density range 30-200 mJy due to the sky area covered. Using the deepest available source count data, we find that the MWA image is affected by sidelobe confusion noise at the ˜3.5 mJy beam-1 level, due to incompletely peeled and out-of-image sources, and classical confusion becomes apparent at ˜1.7 mJy beam-1. This work highlights that (i) further improvements in ionospheric calibration and deconvolution imaging techniques would be required to probe to the classical confusion limit and (ii) the shape of low-frequency source counts, including any flattening towards lower flux densities, must be determined from deeper ˜150 MHz surveys as it cannot be directly inferred from higher frequency data.

dc.publisherOxford University Press
dc.titleThe 154 MHz radio sky observed by the Murchison Widefield Array: Noise, confusion, and first source count analyses
dc.typeJournal Article
dcterms.source.titleMonthly Notices of the Royal Astronomical Society

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

curtin.departmentDepartment of Electrical and Computer Engineering
curtin.accessStatusOpen access

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