Cooray, Asantha and Calanog, Jae and Wardlow, Julie L. and Bock, J. and Bridge, C. and Burgarella, D. and Bussmann, R. S. and Casey, C. M. and Clements, D. and Conley, A. and Farrah, D. and Fu, H. and Gavazzi, R. and Ivison, R. J. and La Porte, N. and Lo Faro, B. and Ma, Brian and Magdis, G. and Oliver, S. J. and Osage, W. A. and Pérez-Fournon, I. and Riechers, D. and Rigopoulou, D. and Scott, Douglas and Viero, M. and Watson, D. (2014) HerMES: The Rest-frame UV Emission and a Lensing Model for the z = 6.34 Luminous Dusty Starburst Galaxy HFLS3. The Astrophysical Journal, 790 (1). p. 40. ISSN 0004-637X
Abstract
We discuss the rest-frame ultraviolet emission from the starbursting galaxy HFLS3 at a redshift of 6.34. The galaxy was discovered in Herschel/SPIRE data due to its red color in the submillimeter wavelengths from 250 to 500 μm. Keck/NIRC2 K s -band adaptive optics imaging data showed two potential near-IR counterparts near HFLS3. Previously, the northern galaxy was taken to be in the foreground at z = 2.1, while the southern galaxy was assumed to be HFLS3's near-IR counterpart. The recently acquired Hubble/WFC3 and Advanced Camera for Surveys (ACS) imaging data show conclusively that both optically bright galaxies are in the foreground at z <6. A new lensing model based on the Hubble imaging data and the millimeter-wave continuum emission yields a magnification factor of 2.2 ± 0.3, with a 95% confidence upper limit on the magnification of 3.5. When corrected for lensing, the instantaneous star formation rate is 1320 M ⊙ yr-1, with the 95% confidence lower limit around 830 M ⊙ yr-1. The dust and stellar masses of HFLS3 from the same spectral energy distribution (SED) models are at the level of 3 × 108 M ⊙ and ~5 × 1010 M ⊙, respectively, with large systematic uncertainties on assumptions related to the SED model. With Hubble/WFC3 images, we also find diffuse near-IR emission about 0.5 arcsec (~3 kpc) to the southwest of HFLS3 that remains undetected in the ACS imaging data. The emission has a photometric redshift consistent with either z ~ 6 or a dusty galaxy template at z ~ 2.