First results from the ATCA 18 GHz pilot survey

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dc.creatorRicci, R.
dc.creatorSadler, E. M.
dc.creatorEkers, R. D.
dc.creatorStaveley-Smith, L.
dc.creatorWilson, W. E.
dc.creatorKesteven, M. J.
dc.creatorSubrahmanyan, R.
dc.creatorWalker, M. A.
dc.creatorJackson, C. A.
dc.creatorDe Zotti, G.
dc.date2004-07-07
dc.date2004-07-09
dc.date.accessioned2026-07-07T02:13:45Z
dc.date.available2026-07-07T02:13:45Z
dc.descriptionAs a pilot study for the first all-sky radio survey at short wavelengths, we have observed 1216 sq. deg. of the southern sky at 18GHz (16mm) using a novel wide-band (3.4GHz bandwidth) analogue correlator on one baseline of the Australia Telescope Compact Array (ATCA). We scanned a region of sky between declination -71 and -59 degrees with an rms noise level of 15mJy. Follow-up radio imaging of candidate sources above a 4 sigma detection limit of 60mJy resulted in 221 confirmed detections, for which we have measured accurate positions and flux densities. For extragalactic sources, the survey is roughly 70% complete at a flux density of 126mJy and 95% complete above 300mJy. Almost half the detected sources lie within a few degrees of the Galactic plane, but there are 123 sources with |b|>5 degrees which can be assumed to be extragalactic. The differential source counts for extragalactic sources in the range 0.1Jy < S_{18GHz} < 3Jy are well fitted by a relation of the form n(S)=57(S/{Jy})^{-2.2\pm0.2} [Jy^-1 sr^-1], in good agreement with the 15GHz counts published by Taylor et al. (2001) and Waldram et al. (2003). Over 70% of the extragalactic sources have a flat radio spectrum (α_{0.843}^{18}> -0.5, S_ν\proptoν^α), and 29% have inverted radio spectra (α_{0.843}^{18}> 0). The optical identification rate is high: 51% of the extragalactic sources are identified with stellar objects (candidate QSOs), 22% with galaxies and only 27% with faint optical objects or blank fields.
dc.description17 pages, 12 figures, 5 tables, accepted by MNRAS, external tables and radio-optical overlays in appendix A can be found at http:/www.sissa.it/~ricci/overlays/
dc.identifierhttps://arxiv.org/abs/astro-ph/0407130
dc.identifierhttp://arxiv.org/abs/astro-ph/0407130
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/7923
dc.subjectAstrophysics
dc.titleFirst results from the ATCA 18 GHz pilot survey
dc.typetext

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