A spectroscopic search for AGN activity in the reionization era Academic Article uri icon


  • The ubiquity of Lyman alpha (Lyα) emission in a sample of four bright [O iii]-strong star- forming galaxies with redshifts above seven has led to the suggestion that such luminous sources represent a distinct population compared with their fainter, more numerous counterparts. The presence of Lyα emission within the reionization era could indicate that these sources created early ionized bubbles due to their unusually strong radiation, possibly because of the presence of active galactic nuclei. To test this hypothesis, we secured long integration spectra with XSHOOTER on the VLT for three $ z\simeq 7$ sources selected to have similar luminosities and prominent excess fluxes in the IRAC 3.6 or 4.5 μm band, usually attributed to strong [O iii] emission. We secured additional spectroscopy for one of these galaxies at z= 7.15 using MOSFIRE at the Keck telescope. For the most well …

publication date

  • January 1, 2017