Negrello, M. and Hopwood, R. and Dye, S. and da Cunha, E. and Serjeant, S. and Fritz, J. and Rowlands, K. and Fleuren, S. and Bussmann, R. S. and Cooray, A. and Dannerbauer, H. and Gonzalez-Nuevo, J. and Lapi, A. and Omont, A. and Amber, S. and Auld, R. and Baes, M. and Buttiglione, S. and Cava, A. and Danese, L. and Dariush, A. and De Zotti, G. and Dunne, L. and Eales, S. and Ibar, E. and Ivison, R. J. and Kim, S. and Leeuw, L. and Maddox, S. and Michałowski, M. J. and Massardi, M. and Pascale, E. and Pohlen, M. and Rigby, E. and Smith, D. J. B. and Sutherland, W. and Temi, P. and Wardlow, J. (2014) Herschel *-ATLAS: deep HST/WFC3 imaging of strongly lensed submillimetre galaxies. Monthly Notices of the Royal Astronomical Society, 440 (3). pp. 1999-2012. ISSN 0035-8711
Abstract
We report on deep near-infrared observations obtained with the Wide Field Camera-3 (WFC3) onboard the Hubble Space Telescope (HST) of the first five confirmed gravitational lensing events discovered by the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). We succeed in disentangling the background galaxy from the lens to gain separate photometry of the two components. The HST data allow us to significantly improve on previous constraints of the mass in stars of the lensed galaxy and to perform accurate lens modelling of these systems, as described in the accompanying paper by Dye et al. We fit the spectral energy distributions of the background sources from near-IR to millimetre wavelengths and use the magnification factors estimated by Dye et al. to derive the intrinsic properties of the lensed galaxies. We find these galaxies to have star-formations rates (SFR) ˜ 400-2000 M⊙ yr-1, with ˜(6-25) × 1010 M⊙ of their baryonic mass already turned into stars. At these rates of star formation, all remaining molecular gas will be exhausted in less than ˜100 Myr, reaching a final mass in stars of a few 1011 M⊙. These galaxies are thus proto-ellipticals caught during their major episode of star formation, and observed at the peak epoch (z ˜ 1.5-3) of the cosmic star formation history of the Universe.