VizieR Online Data Catalog: SCUBA observations of COSMOS galaxies (Casey+, 2013)

We present deep 450μm and 850μm observations of a large, uniformly covered 394arcmin² area in the Cosmic Evolution Survey (COSMOS) field obtained with the Scuba-2 instrument on the James Clerk Maxwell Telescope (JCMT). We achieve root-mean-square noise values of σ₄₅₀=4.13mJy and σ₈₅₀=0.80mJy. The differential and cumulative number counts are presented and compared to similar previous works. Individual point sources are identified at >3.6σ significance, a threshold corresponding to a 3-5% sample contamination rate. We identify 78 sources at 450μm and 99 at 850μm, with flux densities S₄₅₀=13-37mJy and S₈₅₀=2-16mJy. Only 62-76% of 450μm sources are 850μm detected and 61-81% of 850μm sources are 450μm detected. The positional uncertainties at 450μm are small (1-2.5 arcsec) and therefore allow a precise identification of multiwavelength counterparts without reliance on detection at 24μm or radio wavelengths; we find that only 44% of 450μm sources and 60% of 850μm sources have 24μm or radio counterparts. 450μm selected galaxies peak at <z>=1.95+/-0.19 and 850μm selected galaxies peak at <z>=2.16+/-0.11. The two samples occupy similar parameter space in redshift and luminosity, while their median SED peak wavelengths differ by ~20-50μm (translating to ΔT_dust=8-12K, where 450μm selected galaxies are warmer). The similarities of the 450μm and 850μm populations, yet lack of direct overlap between them, suggests that submillimetre surveys conducted at any single far-infrared wavelength will be significantly incomplete (>~30%) at censusing infrared-luminous star formation at high z.

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