MULTI-WAVELENGTH LENS RECONSTRUCTION OF A PLANCK AND HERSCHEL- DETECTED STAR-BURSTING GALAXY

International audienceWe 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 similar to 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-circle dot yr(-1) and a stellar mass of 1.1 +/- 0.4 x 10(11) M-circle dot. 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-circle dot pc(-2), and similar to 12 +/- 7 M-circle dot 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