The XMM-Newton wide-field survey in the COSMOS field

Context. The COSMOS survey is a multiwavelength survey aimed to study the evolution of galaxies, AGN and large scale structures. Within this survey XMM-COSMOS a powerful tool to detect AGN and galaxy clusters. The XMM-COSMOS is a deep X-ray survey over the full 2 deg2 of the COSMOS area. It consists of 55 XMM-Newton pointings for a total exposure of ∼1.5 Ms with an average vignetting-corrected depth of 40 ks across the field of view and a sky coverage of 2.13 deg2. Aims. We present the catalogue of point-like X-ray sources detected with the EPIC CCD cameras, the log N − log S relations and the X-ray colour–colour diagrams. Methods. The analysis was performed using the XMM-SAS data analysis package in the 0.5–2 keV, 2–10 keV and 5–10 keV energy bands. Source detection has been performed using a maximum likelihood technique especially designed for raster scan surveys. The completeness of the catalogue as well as log N − log S and source density maps have been calibrated using Monte Carlo simulations. Results. The catalogs contains a total of 1887 unique sources detected in at least one band with likelihood parameter det_ml > 10. The survey, which shows unprecedented homogeneity, has a flux limit of ∼1.7×10−15 erg cm−2 s−1, ∼9.3×10−15 erg cm−2 s−1 and ∼1.3×10−14 erg cm−2 s−1 over 90% of the area (1.92 deg) in the 0.5–2 keV, 2–10 keV and 5–10 keV energy band, respectively. Thanks to the rather homogeneous exposure over a large area, the derived log N − log S relations are very well determined over the flux range sampled by XMM-COSMOS. These relations have been compared with XRB synthesis models, which reproduce the observations with an agreement of ∼10% in the 5–10 keV and 2–10 keV band, while in the 0.5–2 keV band the agreement is of the order of ∼20%. The hard X-ray colors confirmed that the majority of the extragalactic sources in a bright subsample are actually type I or type II AGN. About 20% of the sources have a X-ray luminosity typical of AGN (LX > 1042 erg/s) although they do not show any clear signature of nuclear activity in the optical spectrum.