Spitzer Imaging of Herschel-atlas Gravitationally Lensed Submillimeter Sources

Hopwood, R. and Wardlow, J. and Cooray, A. and Khostovan, A. A. and Kim, S. and Negrello, M. and da Cunha, E. and Burgarella, D. and Aretxaga, I. and Auld, R. and Baes, M. and Barton, E. and Bertoldi, F. and Bonfield, D. G. and Blundell, R. and Buttiglione, S. and Cava, A. and Clements, D. L. and Cooke, J. and Dannerbauer, H. and Dariush, A. and de Zotti, G. and Dunlop, J. and Dunne, L. and Dye, S. and Eales, S. and Fritz, J. and Frayer, D. and Gurwell, M. A. and Hughes, D. H. and Ibar, E. and Ivison, R. J. and Jarvis, M. J. and Lagache, G. and Leeuw, L. and Maddox, S. and Michałowski, M. J. and Omont, A. and Pascale, E. and Pohlen, M. and Rigby, E. and Rodighiero, G. and Scott, D. and Serjeant, S. and Smail, I. and Smith, D. J. B. and Temi, P. and Thompson, M. A. and Valtchanov, I. and van der Werf, P. and Verma, A. and Vieira, J. D. (2011) Spitzer Imaging of Herschel-atlas Gravitationally Lensed Submillimeter Sources. Astrophysical Journal Letters, 728 (1). ISSN 2041-8205

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Abstract

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