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arXiv 1302.2619astro-ph.CO
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SCUBA-2 450 μ m和850 μ m选择镓在COSMOS领域的表征

Characterisation of SCUBA-2 450um and 850um-selected Galaxies in the COSMOS Field

Caitlin M. Casey, Chian-Chou Chen, Lennox Cowie, Amy Barger, Peter Capak, Olivier Ilbert, Michael Koss, Nicholas Lee, Emeric Le Floc'h, David B. Sanders, Jonathan P. Williams

摘要:

我们将介绍利用詹姆斯·克拉克·麦克斯韦望远镜(JCMT)上的SCUBA-2仪器对COSMOS场中一个面积为394弧分^[2]的大面积均匀覆盖区域进行的450 μ m和850 μ m深度的观测。在450um和850um处,我们实现了4.13mJy和0.80mJy的均方根噪声值。的差异和累积数计数,并与以前类似的作品。单个点源在> 3.6sigma显著性下被识别,该阈值对应于3 - 5%的样品污染率。在450 μ m和850 μ m处分别识别出78个和99个源,其通量密度分别为S450 = 13 - 37mJy和S850 = 2 - 16mJy。只有62 - 76%的450um源是850um检测和61 - 81%的850um源是450um检测。450微米的位置不确定性很小(1 - 2.5 "),因此可以精确识别多波长对应物,而不依赖于24微米或射电波长的探测;我们发现只有44%的450微米选定星系和60%的850微米源有24微米或射电对应物。450微米选定星系的峰值在= 1.95 +-0.19,850微米选定星系的峰值在= 2.16 +-0.11。<z><z>这两个样本在红移和光度上占据了相似的参数空间,而它们的SED峰值波长中值相差约10 - 50 μ m(转换为δ T dust = 8 - 12 K,其中450 μ m的星系更温暖)。450 um和850 um星群的相似性,但它们之间缺乏直接的重叠,这表明在任何单一远红外波长下进行的亚毫米波调查在普查高Z下的红外发光恒星形成时都是非常不完整的(~&gt; 30%)。

英文摘要:

We present deep 450um and 850um observations of a large, uniformly covered 394arcmin^2 area in the COSMOS field obtained with the SCUBA-2 instrument on the James Clerk Maxwell Telescope (JCMT). We achieve root-mean-square noise values of 4.13mJy at 450um and 0.80mJy at 850um. The differential and cumulative number counts are presented and compared to similar previous works. Individual point sources are identified at >3.6sigma significance, a threshold corresponding to a 3-5% sample contamination rate. We identify 78 sources at 450um and 99 at 850um, with flux densities S450=13-37mJy and S850=2-16mJy. Only 62-76% of 450um sources are 850um detected and 61-81% of 850um sources are 450um detected. The positional uncertainties at 450um are small (1-2.5") and therefore allow a precise identification of multiwavelength counterparts without reliance on detection at 24um or radio wavelengths; we find that only 44% of 450um-selected galaxies and 60% of 850um-sources have 24um or radio counterparts. 450um-selected galaxies peak at <z>=1.95+-0.19 and 850um=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 ~10-50um (translating to deltaTdust =8-12K, where 450um-selected galaxies are warmer). The similarities of the 450um and 850um populations, yet lack of direct overlap between them, suggests that submillimeter 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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