XMM-Newton observation of the Lockman Hole^*

I. The X-ray data

¹ Astrophysikalisches Institut Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
² Operations Centre, European Space Agency, Vilspa, Apartado 50727, 28080 Madrid, Spain
³ CEA/DSM/DAPNIA/Service d'Astrophysique, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France
⁴ Instituto de Fisica (Consejo Superior de Investigaciones Cientificas-Universidad de Cantabria), 39005 Santander, Spain
⁵ European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching, Germany
⁶ TeSRE-CNR, Via Gobetti 101, 40129 Bologna, Italy
⁷ Max-Planck-Institut für extraterrestrische Physik, 85740 Garching, Germany
⁸ Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA 15213, USA
⁹ Space Science Dept., European Space Agency, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
¹⁰ MSSL, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
¹¹ Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
¹² Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street, New York, NY 10027, USA
¹³ Department of Physics, University of California at Santa Barbara, Santa Barbara, CA 93110, USA
¹⁴ X-ray Astronomy Group, Department of Physics and Astronomy, Leicester University, Leicester LE1 7RH, UK

Corresponding author: G. Hasinger, ghasinger@aip.de

Received: 2 October 2000
Accepted: 24 October 2000

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 , 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.