The XMM‐Newton Wide‐Field Survey in the COSMOS Field. II. X‐Ray Data and the log  N ‐log  S Relations

We present data analysis and X-ray source counts for the first season of-Newton observations in the COSMOS field. The survey covers ~2² within the region of sky bounded by09h57m30s<R.A.<10h03m30s,01deg27'30''<decl.<02deg57'30'' a total net integration time of 504 ks. A maximum likelihood source was performed in the 0.5-2, 2-4.5, and 4.5-10 keV energy, and 1390 pointlike sources were detected in at least one band. Monte Carlo simulations were performed to fully test the-detection method and to derive the sky coverage to be used in the of the logN-logS relations. These relations were then in the 0.5-2, 2-10, and 5-10 keV energy bands, down to flux of 7.2×10⁻¹⁶ ergs cm⁻²⁻¹, 4.0×10⁻¹⁵ ergs cm⁻²⁻¹, and 9.7×10⁻¹⁵ ergs cm⁻²⁻¹, respectively. Thanks to the large number of sources in the COSMOS survey, the logN-logS curves are tightly over a range of fluxes which were poorly covered by previous, especially in the 2-10 and 5-10 keV bands. The 0.5-2 and 2-10 differential logN-logS relations were fitted with a broken power-law which revealed a Euclidean slope at the bright end and a flatter (α~1.5) at faint fluxes. In the 5-10 keV energy band a power law provides an acceptable fit to the observed source with a slope α~2.4. A comparison with the results of surveys shows good agreement in all the energy bands under in the overlapping flux range. We also notice a remarkable between our logN-logS relations and the most recent model of X-ray background. on observations obtained with XMM-Newton, an ESA science mission instruments and contributions directly funded by ESA Member States NASA; also based on data collected at the Canada-France-Hawaii operated by the National Research Council of Canada, the National de la Recherche Scientifique de France, and the of Hawaii.