Gamma-ray blazars within the first two billion years

MeV blazars, with a high-energy peak in the MeV band, are the most powerful persistent sources in the Universe, exhibiting larger-than-average jet powers, accretion luminosities, and black hole masses. Their detection above redshift 3 has the power to constrain the formation mechanism of heavy black holes. Here we report the first detection with the Fermi Large Area Telescope of gamma-ray emitting blazars beyond redshift 3. The newly detected objects have black-hole masses in excess of 1 billion solar masses and very prominent disk and gamma-ray emission. We will discuss the new finding within the context of blazar evolution and the disk-jet connection in powerful jetted AGN.