XMM-Newton observation of the Lockman Hole. I. The X-ray data
Finoguenov, A.; Altieri, B.; Arnaud, M.; Page, M. J.; Schartel, N.; Barcons, X.; Hasinger, G.; Dadina, M.; Warwick, R. S.; Watson, M. G.; Ferrando, P.; Griffiths, R. E.; Trümper, J.; Brunner, H.; Mateos, S.; Mason, K. O.; Jansen, F. A.; Bergeron, J.; Dennerl, K.; McMahon, R. G.; Paerels, F.; Miyaji, T.; Ptak, A. F.; Lumb, D. H.; Sasseen, T. P.; Turner, M.; Szokoly, G. P.; Hashimoto, Y.
Germany, Spain, France, Italy, United States, Netherlands, United Kingdom
Abstract
We report on the first deep X-ray survey with the XMM-Newton observatory during the performance verification phase. The field of the Lockman Hole, one of the best studied sky areas over a very wide range of wavelengths, has been observed. A total of ~ 100 ksec good exposure time has been accumulated. Combining the images of the European Photon Imaging Camera (EPIC) detectors we reach a flux limit of 0.31, 1.4 and 2.4 ; 10-15 erg cm-2 s-1, respectively in the 0.5-2, 2-10, and 5-10 keV band. Within an off-axis angle of 10 arcmin we detect 148, 112 and 61 sources, respectively. The log(N)-log(S) relation in the three bands is compared with previous results. In particular in the 5-10 keV band these observations present the deepest X-ray survey ever, about a factor 20 more sensitive than the previous BeppoSAX observations. Using X-ray spectral diagnostics and the set of previously known, spectroscopically identified ROSAT sources in the field, the new sources can be classified. XMM-Newton detects a significant number ( ~ 40%) of X-ray sources with hard, probably intrinsically absorbed X-ray spectra, confirming a prediction of the population synthesis models for the X-ray background. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).