AzTEC millimetre survey of the COSMOS field – III. Source catalogue over 0.72 deg^(2) and plausible boosting by large-scale structure
Wilson, Graham Wallace
Scott, K. S.
Yun, M. S.
Austermann, J. E.
Downes, T. P.
Hughes, D. H.
Perera, Thushara A.
Oxford University Press
Scholarly/refereed, publisher version
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We present a 0.72 deg2 contiguous 1.1-mm survey in the central area of the Cosmological Evolution Survey field carried out to a 1σ≈ 1.26 mJy beam−1 depth with the AzTEC camera mounted on the 10-m Atacama Submillimeter Telescope Experiment. We have uncovered 189 candidate sources at a signal-to-noise ratio (S/N) ≥ 3.5, out of which 129, with S/N ≥ 4, can be considered to have little chance of being spurious (≲2 per cent). We present the number counts derived with this survey, which show a significant excess of sources when compared to the number counts derived from the ∼0.5 deg2 area sampled at similar depths in the Submillimetre Common-User Bolometer Array (SCUBA) HAlf Degree Extragalactic Survey (SHADES). They are, however, consistent with those derived from fields that were considered too small to characterize the overall blank-field population. We identify differences to be more significant in the S1.1mm≳ 5 mJy regime, and demonstrate that these excesses in number counts are related to the areas where galaxies at redshifts z≲ 1.1 are more densely clustered. The positions of optical–infrared galaxies in the redshift interval 0.6 ≲z≲ 0.75 are the ones that show the strongest correlation with the positions of the 1.1-mm bright population (S1.1mm≳ 5 mJy), a result which does not depend exclusively on the presence of rich clusters within the survey sampled area. The most likely explanation for the observed excess in number counts at 1.1-mm is galaxy–galaxy and galaxy–group lensing at moderate amplification levels, which increases in amplitude as one samples larger and larger flux densities. This effect should also be detectable in other high-redshift populations.
This article has been accepted for publication in Monthly Notices Of The Royal Astronomical Society ©: 2011. Aretxaga et al. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Aretxaga, I. et al. (2011). "AzTEC millimetre survey of the COSMOS field – III. Source catalogue over 0.72 deg^(2) and plausible boosting by large-scale structure." Monthly Notices Of The Royal Astronomical Society, 415(4):3831-3850. http://www.dx.doi.org/10.1111/j.1365-2966.2011.18989.x.
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