[BCH2008] 99 , the SIMBAD biblio

The Lockman Hole field represents the sky area of lowest Galactic line-of-sight column density N_H=5.7x10¹⁹cm^–2. It was observed by the XMM-Newton X-ray observatory in 18 pointings for a total of 1.16Ms (raw EPIC pn observing time) constituting the deepest XMM-Newton exposure so far. After the removal of time intervals with high particle background, the final effective exposure was 637ks. We present a catalogue of the X-ray sources detected in the central 0.196deg² of the field and discuss the derived number counts and X-ray colours. The analysis was performed using the XMM-SAS data analysis package version 6.0. The detection sensitivity and fraction of spurious detections was calibrated using Monte Carlo simulations. In the 0.5-2.0keV band, a sensitivity limit (defined as the faintest detectable source) of 1.9x10^–16erg/cm2/s was reached. The 2.0-10.0keV band and 5.0-10.0keV band sensitivity limits were 9x10^–16erg/cm2/s and 1.8x10^–15erg/cm2/s, respectively. A total of 409 sources above a detection likelihood of 10 (3.9sigma) were found within a radius of 15' off the field centre, of which 340, 266, and 98 sources were detected in the soft, hard, and very hard bands, respectively. The number counts in each energy band are in close agreement with results from previous surveys and with the synthesis models of the X-ray background. Six percent of the Compton-thick source candidates have been selected from the X-ray colour-colour diagram. This fraction is consistent with the most recent predictions of X-ray background population synthesis models at our flux limits. We also estimated, for the first time, the logN-logS relation for Compton-thick AGN.