CHARACTERIZING FAINT GALAXIES IN THE REIONIZATION EPOCH: LBT CONFIRMS TWO L< 0.2 L⋆ SOURCES AT z= 6.4 BEHIND THE CLASH/FRONTIER FIE... Academic Article uri icon

abstract

  • We report the LBT/MODS1 spectroscopic confirmation of two images of faint Lyα emitters at z= 6.4 behind the Frontier Fields galaxy cluster MACSJ0717. 5+ 3745. A wide range of lens models suggests that the two images are highly magnified, with a strong lower limit of μ> 5. These are the faintest z> 6 candidates spectroscopically confirmed to date. These may also be multiple images of the same z= 6.4 source as supported by their similar intrinsic properties, but the lens models are inconclusive regarding this interpretation. To be cautious, we derive the physical properties of each image individually. Thanks to the high magnification, the observed near-infrared (restframe ultraviolet) part of the spectral energy distributions and Lyα lines are well detected with S/N (m 1500) gsim 10 and S/N (Lyα) sime 10-15. Adopting μ> 5, the absolute magnitudes, M 1500, and Lyα fluxes are fainter than …

publication date

  • February 14, 2014