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Multi-wavelength Lens Reconstruction of a Planck and Herschel-detected Star-bursting Galaxy

N. Timmons, A. Cooray, D. A. Riechers, H. Nayyeri, H. Fu, E. Jullo, M. D. Gladders, M. Baes, R. S. Bussmann, Jae Calanog, D. L. Clements, E. Cunha, S. Dye, S. Eales, C. Furlanetto, J. GonzŠlez-Nuevo, J. Greenslade, M. Gurwell, H. Messias, M. J. Michałowski, I. Oteo, I. Pťrez-Fournon, D. Scott, E. Valiante

Abstract
We present a source-plane reconstruction of a Herschel and Planck-detected gravitationally lensed dusty star-forming galaxy (DSFG) at z = 1.68 using Hubble, Submillimeter Array (SMA), and Keck observations. The background submillimeter galaxy (SMG) is strongly lensed by a foreground galaxy cluster at z = 0.997 and appears as an arc with a length of ~15″ in the optical images. The continuum dust emission, as seen by SMA, is limited to a single knot within this arc. We present a lens model with source-plane reconstructions at several wavelengths to show the difference in magnification between the stars and dust, and highlight the importance of multi-wavelength lens models for studies involving lensed DSFGs. We estimate the physical properties of the galaxy by fitting the flux densities to model spectral energy distributions leading to a magnification-corrected star-formation rate (SFR) of 390 ± 60 M yr-1 and a stellar mass of 1.1 ± 0.4×1011 M. These values are consistent with high-redshift massive galaxies that have formed most of their stars already. The estimated gas-to-baryon fraction, molecular gas surface density, and SFR surface density have values of 0.43 ± 0.13, 350 ± 200 M pc-2, and ~12 ± 7 M yr-1 kpc-2, respectively. The ratio of SFR surface density to molecular gas surface density puts this among the most star-forming systems, similar to other measured SMGs and local ULIRGs.

Keywords
cosmology: observations, galaxies: evolution, infrared: galaxies, submillimeter: galaxies

The Astrophysical Journal
Volume 829, Number 1
2016 September

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Instituto de Astrof√≠sica e Ci√™ncias do Espa√ßo Universidade do Porto Faculdade de Ciências da Universidade de Lisboa
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia