Campus, PAB 102/103
Observations indicate that supermassive black holes (SMBHs, 10**6-10**9 Msun) dwell at the centers of most local galaxies. Scaling relations between SMBH mass and several large-scale properties of the host galaxies point to a co-ordindated growth of galaxies and their central engines over cosmic time: they "co-evolve". Who is the leading actor on the the cosmic stage: the black hole or the galaxy? Is black hole activity triggering star-formation or suppressing it? Viceversa, does the galaxy control the black hole growth? How long their relationship has been going on? Observational works to address these questions give controversial results. In this talk I will present my work focusing on SMBH growth mechanisms, accretion and mergers, to understand these processes, and their signatures at high redshift and for faint sources. I will use the extraordinarily rich multiwavelength dataset of the Cosmic Evolutionary Survey (COSMOS), focusing on the highest energy data available, the X-ray ones. These data provide us with a unique and powerful tool to find and study obscured accreting SMBHs in the distant Universe.