Program: GN-2015B-FT-22

GB6 0906+6930, a bright radio source at z=5.48, is the blazar with the highest known redshift. Although it was found in a survey targeting excesses of EGRET gamma-ray photons, it has not been detected by the Fermi LAT. This is peculiar since it has a strong X-ray synchrotron self-Compton component, while optical/IR fluxes indicate a bright disk and broad-line region which should produce gamma-rays via external Compton scattering. We request a GNRIS near-IR spectrum, to measure the thermal disk continuum and BLR covering fraction and estimate the black hole mass. This allows us to improve synchro-Compton models to understand its gamma-ray reticence.