ATLAS – I. Third release of 1.4 GHz mosaics and component catalogues

Abstract

We present the third data release from the Australia Telescope Large Area\nSurvey (ATLAS). These data combine the observations at 1.4 GHz before and after\nupgrades to the Australia Telescope Compact Array reaching a sensitivity of 14\nmicroJy/beam in 3.6 deg^2 over the Chandra Deep Field South (CDFS) and of 17\nmicroJy/beam in 2.7 deg^2 over the European Large Area ISO Survey South 1\n(ELAIS-S1). We used a variety of array configurations to maximise the uv\ncoverage resulting in a resolution of 16 by 7 arcsec in CDFS and of 12 by 8\narcsec in ELAIS-S1. After correcting for peak bias and bandwidth smearing, we\nfind a total of 3034 radio source components above 5 sigma in CDFS, of which\n514 (17 per cent) are considered to be extended. The number of components\ndetected above 5 sigma in ELAIS-S1 is 2084, of which 392 (19 per cent) are\nclassified as extended. The catalogues include reliable spectral indices (delta\nalpha < 0.2) between 1.40 and 1.71 GHz for ~350 of the brightest components.\n