Fabrizio Fiore (Osservatorio Astronomico di Roma)
Jeudi 18 Octobre - 11 h 00
Salle Manuel Forestini - IPAG
AGN observations and evolutionary studies can be used to investigate the physics of baryon transformation in galaxies and the cosmological framework. I will present a pilot program to push the search of unobscured and obscured AGN up to z=5-6 and discuss the astrophysical and cosmological perspectives of this line of research. Targeting high-z supermassive black holes (SMBHs), the structures with the fastest (exponential) growth rate, can help investigating the evolution of the Universe at those early epochs, because little differences in the time of expansion of the Universe can be significantly emphasized. By comparing the high-z SMBH mass function to model predictions we might on one side disentangle competing cosmological scenarios, and on the other side put constraints on SMBH seed scenarios, the physics of accretion and AGN triggering mechanisms. I will then discuss interactions and links between the nuclear SMBHs and their host galaxies. The SMBH/AGN/galaxy co-evolution depends on some physical mechanism (’feedback’) linking accretion and ejection occurring on sub-parsec scale in galaxy nuclei to the transformations occurring in the rest of the galaxy. I will present searches for "direct" evidence of AGN feedback in bright nearby, high-luminosity, highly obscured QSOs, and discuss the perspectives of extending these studies up tp z=1-3, the golden epoch of AGN and galaxy activity.
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