Scientific Seminars

The demography of obscured AGN

Andrea Comastri
INAF-OABO

2015-04-14    14:00    Brera - Cupola Fiore

According to recent models for the joint growth of Super Massive Black Holes and their Host Galaxies, heavy, possibly Compton thick, obscuration represents a key phase in their evolution and is expected to play a fundamental role in the feedback mechanisms linking SMBH activity with host galaxy properties. A recent revision of the scaling relations indicate that the local mass density in black holes could be significantly higher (by a factor 2-4) than previously thought. A possible explanation would be in terms of an increased fraction of the deeply buried Compton thick AGN. I will discuss to what extent a population of ultra obscured AGN could be accommodated in the current observational picture without violating the limits imposed by the hard X-ray and mid-infrared backgrounds spectral energy density. I will review of the key results obtained by deep Chandra and XMM surveys over the last 15 years and the current hard X-ray (3-80 keV) observations with NuSTAR in the search for and characterization of heavily obscured SMBH. I will conclude presenting the perspectives for future observations with the ESA Large mission ATHENA.