Clustering of the Cosmic X-ray Background sources and surface brightness: inspecting beyond limit of current X-ray surveys
Nico Cappelluti

In this talk I will present the status of the art of the studies on AGN clustering in the X-ray band and its applications in understanding the coeval growth of SMBH and Dark Matter Halos. A well defined picture has been taken up to z~2 while, at high-z, where important physical phenomena connected with SMBH formation take place, the knowledge is still relegated to the study of anisotropies of the unresolved CXB. I will finally present recent applications of clustering analysis to the study of clustering patterns of the unresolved CXB fluctuations and their counterparts at IR wavelengths. Finally, I will present the detection of a possible signature of the first BH in the Universe, through CIB-CXB cross-fluctuation analysis.