Supermassive black holes at high redshifts

Vaidehi S. Paliya, Marco Ajello, Lea Marcotulli, John Tomsick, Jeremy S. Perkins, Elisa Prandini, Filippo D'Ammando, Alessandro De Angelis, David Thompson, Hui Li, Alberto Dominguez, Volker Beckmann, Sylvain Guiriec, Zorawar Wadiasingh, Paolo Coppi, J. Patrick Harding, Maria Petropoulou, John W. Hewitt, Roopesh Ojha, Alexandre Marcowith, Michele Doro, Daniel Castro, Matthew Baring, Elizabeth Hays, Elena Orlando, Sylvain Guiriec, Vladimir Bozhilov, Ivan Agudo, Tonia Venters, Julie McEnery, Lih-Sin The, Dieter Hartmann, Sara Buson, Francesco Longo, Dario Gasparrini

Published 2019-03-14Version 1

MeV blazars are the most luminous persistent sources in the Universe and emit most of their energy in the MeV band. These objects display very large jet powers and accretion luminosities and are known to host black holes with a mass often exceeding $10^9 M_{\odot}$. An MeV survey, performed by a new generation MeV telescope which will bridge the entire energy and sensitivity gap between the current generation of hard X-ray and gamma-ray instruments, will detect $>$1000 MeV blazars up to a redshift of $z=5-6$. Here we show that this would allow us: 1) to probe the formation and growth mechanisms of supermassive black holes at high redshifts, 2) to pinpoint the location of the emission region in powerful blazars, 3) to determine how accretion and black hole spin interplay to power the jet.