Objective We propose to use X-ray data from two pioneering in their kind and complementary multi-wavelength surveys, in order to perform a systematic study of obscured AGN. These leverage substantial investments of space- and ground-based telescope time, yielding a unique dataset to study the obscured Universe. The elusive population of obscured AGN most likely dominates the population of accreting super massive black holes, however, it remains mostly undetected.The impact of multi-wavelength observations for the study of AGN is crucial and the only way to obtain accurate demographics of obscured AGN at high red shift. If our findings will show substantial and widespread obscuration, this will have important implications for the cosmic accretion history of black holes. The pro posed collaboration will promote the professional reintegration of the proposed researcher and will help expanding the activities of the X-ray group of the Institute of Astronomy and Astrophysics of the National Observatory of Athens, by blending the fields of expertise of the researchers involved and by combining the unique datasets to which each party has access. Fields of science humanitieshistory and archaeologyhistorynatural sciencesphysical sciencesastronomyastrophysicsblack holesnatural sciencesmathematicspure mathematicsgeometry Programme(s) FP6-MOBILITY - Human resources and Mobility in the specific programme for research, technological development and demonstration "Structuring the European Research Area" under the Sixth Framework Programme 2002-2006 Topic(s) MOBILITY-4.2 - Marie Curie International Reintegration Grants (IRG) Call for proposal FP6-2002-MOBILITY-12 See other projects for this call Funding Scheme IRG - Marie Curie actions-International re-integration grants Coordinator NATIONAL OBSERVATORY OF ATHENS EU contribution No data Address LOFOS NYMFON, THESIO ATHENS Greece See on map Links Website Opens in new window Total cost No data