| Summary: | We present APEX SABOCA 350 μm and LABOCA 870 μm observations of 11 representative examples of the rare, extremely bright (_( 1.4 mm) > 15 mJy), dust-dominated millimeter-selected galaxies recently discovered by the South Pole Telescope. All 11 sources are robustly detected with LABOCA with 40 mJy < S_(870 μm) < 130 mJy, approximately an order of magnitude higher than the canonical submillimeter galaxy (SMG) population. Six of the sources are also detected by SABOCA at >3σ, with the detections or upper limits providing a key constraint on the shape of the spectral energy distribution (SED) near its peak. We model the SEDs of these galaxies using a simple modified blackbody and perform the same analysis on samples of SMGs of known redshift from the literature. These calibration samples inform the distribution of dust temperature for similar SMG populations, and this dust temperature prior allows us to derive photometric redshift estimates and far-infrared luminosities for the sources. We find a median redshift of z = 3.0, higher than the z = 2.2 inferred for the normal SMG population. We also derive the apparent size of the sources from the temperature and apparent luminosity, finding them to appear larger than our unlensed calibration sample, which supports the idea that these sources are gravitationally magnified by massive structures along the line of sight. © 2012 American Astronomical Society. Received 2011 December 5; accepted 2012 June 19; published 2012 August 20. The authors thank A. Blain and N. Scoville for stimulating discussions and guidance. We are grateful to the competent staff at the APEX base camp in Sequitor, Chile. The South Pole Telescope is supported by the National Science Foundation through grants ANT-0638937 and ANT-0130612. Partial support is also provided by the NSF Physics Frontier Center grant PHY-0114422 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation, and the Gordon and Betty Moore Foundation. T.R.G. acknowledges ...
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