We present physical properties of two submillimeter selected gravitationally lensed sources, identified in theudHerschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densitiesud>100 mJy at 500 μm, but are not visible in existing optical imaging. We fit light profiles to each component ofudthe lensing systems in Spitzer IRAC 3.6 and 4.5 μm data and successfully disentangle the foreground lens fromudthe background source in each case, providing important constraints on the spectral energy distributions (SEDs)udof the background SMG at rest-frame optical–near-infrared wavelengths. The SED fits show that these two SMGsudhave high dust obscuration with A_V ~ 4–5 and star formation rates of ~100M_⊙ yr^(−1). They have low gas fractionsudand low dynamical masses compared with 850 μm selected galaxies.
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