Mass function of dormant black holes and the evolution of the Active   Galactic Nuclei
  We derive the mass function of the relic black holes and compared with that of the Massive Dark Objects in galaxies. Under the assumption that accretion onto massive BH's powers the Active Galactic Nuclei, the mass function of the BH responsibile for the past activity of QSO/AGN is computed. Our results support the scenario in which the QSO phase has exclusively occurred in every proto-elliptical. 
Paolo Salucci, Ewa Szuszkiewicz, Pierluigi Monaco, Luigi Danese