The LABOCA survey of the Extended Chandra Deep Field-South - radio and mid-infrared counterparts to submillimetre galaxies

Biggs, A. D. and Ivison, R. J. and Ibar, E. and Wardlow, J. L. and Dannerbauer, H. and Smail, Ian and Walter, F. and Weiß, A. and Chapman, S. C. and Coppin, K. E. K. and De Breuck, C. and Dickinson, M. and Knudsen, K. K. and Mainieri, V. and Menten, K. and Papovich, C. (2011) The LABOCA survey of the Extended Chandra Deep Field-South - radio and mid-infrared counterparts to submillimetre galaxies. Monthly Notices of the Royal Astronomical Society, 413 (4). pp. 2314-2338. ISSN 0035-8711

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Abstract

We present radio and infrared (3.6-24 μm) counterparts to submillimetre galaxies (SMGs) detected in the Extended Chandra Deep Field-South with the Large APEX Bolometer Camera (LABOCA) 870-μm bolometer camera on the 12-m Atacama Pathfinder Experiment. Using the Very Large Array at 1.4 GHz and Spitzer, we have identified secure counterparts to 79 of the 126 SMGs [signal-to-noise ratio (S/N) > 3.7, S870 > 4.4 mJy] in the field, 62 via their radio and/or 24-μm emission, the remainder using a colour-flux cut on Infrared Array Camera 3.6- and 5.8-μm sources chosen to maximize the number of secure, coincident radio and 24-μm counterparts. In constructing our radio catalogue, we have corrected for the effects of 'flux boosting', then used the corrected flux densities to estimate the redshifts of the SMGs based on the radio/submm spectral indices. The effect of the boosting correction is to increase the median redshift by 0.2 resulting in a value of ? (1σ errors) for the secure radio counterparts, in agreement with other studies, both spectroscopic and photometric.