ROSAT X-ray sources in the field of the LMC^*

II. Statistics of background AGN and X-ray binaries

Sternwarte, Universität Bonn Auf dem Hügel 71, 53121 Bonn, Germany

Corresponding author: pkahabka@astro.uni-bonn.de

Received: 3 September 2001
Accepted: 22 March 2002

Abstract

About 200 X-ray sources from a sample of spectrally hard ROSAT  PSPC sources, given in the catalog of Haberl & Pietsch (1999), and observed in a ~60 square degree field of the LMC during several archival pointed observations with a wide range of exposure times have been reanalyzed. For these sources accurate count rates and hardness ratios have been recalculated. In comparison to Haberl & Pietsch (1999) we used merged data from all available observations and we derived average source parameters by investigating each source individually. From a simulation powerlaw spectral tracks have been derived in the – plane and ~170 sources have been classified as background X-ray sources or as LMC X-ray binaries. 80% of the spectrally hard X-ray sources with more than 50 observed counts have been found to be consistent with background X-ray sources and 20% with LMC X-ray binaries (53 sources with AGN and 15 with X-ray binaries). The discovery of a new supersoft source RX J0529.4-6713 at the southern   boundary of the supergiant shell LMC 4 is reported. We find two new candidate X-ray binary systems which are associated with the optical bar of the LMC and additional candidate X-ray binaries which are associated with supergiant shells.