SIMBAD references

We present data analysis and X-ray source counts for the first season of XMM-Newton observations in the COSMOS field. The survey covers ∼2 deg² within the region of sky bounded by 09^h57^m30^s<R.A.<10^h03^m30^s, 01°27'30"<decl.<02°57'30" with a total net integration time of 504 ks. A maximum likelihood source detection was performed in the 0.5-2, 2-4.5, and 4.5-10 keV energy bands, and 1390 pointlike sources were detected in at least one band. Detailed Monte Carlo simulations were performed to fully test the source-detection method and to derive the sky coverage to be used in the computation of the logN-logS relations. These relations were then derived in the 0.5-2, 2-10, and 5-10 keV energy bands, down to flux limits of 7.2x10^–16 ergs/cm2/s, 4.0x10^–15 ergs/cm2/s, and 9.7x10^–15 ergs/cm2/s, respectively. Thanks to the large number of sources detected in the COSMOS survey, the logN-logS curves are tightly constrained over a range of fluxes which were poorly covered by previous surveys, especially in the 2-10 and 5-10 keV bands. The 0.5-2 and 2-10 keV differential logN-logS relations were fitted with a broken power-law model which revealed a Euclidean slope at the bright end and a flatter slope (α∼1.5) at faint fluxes. In the 5-10 keV energy band a single power law provides an acceptable fit to the observed source counts with a slope α∼2.4. A comparison with the results of previous surveys shows good agreement in all the energy bands under investigation in the overlapping flux range. We also notice a remarkable agreement between our logN-logS relations and the most recent model of the X-ray background.