An XMM-Newton view of the serendipitous sources in the PKS0312-770 field

We describe an XMM-Newton observation of the PKS0312-770 field, which facilitates the spectral analysis of serendipitous sources previously detected by CHANDRA. The combination of larger effective area and longer exposure duration allows a significant increase in detected photons, and a lower limit in source detection sensitivity. In particular the hard X-ray normal galaxy unveiled by Fiore et al. (2000) is most likely explained as a moderately absorbed (N_H ~ 10²² cm^-2) AGN. We detect 52 sources (45 previously unreported) at a limiting flux of ~ 2x 10^-15 ergs cm^-2 s^-1 in the 0.5-2 keV band. The Log N-Log S curve is consistent with that derived from by XMM-Newton observations of the Lockman Hole field. The flux determinations allow to check for any inconsistency between the calibrations of the two observatories, which is discussed.} This work is based on observations made with the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA).