A ROSAT PSPC catalogue of X-ray sources in the LMC region

Abstract

We analyzed more than 200 ROSAT PSPC observations in a 10 by 10 degree field centered on the Large Magellanic Cloud (LMC) and performed between 1990 and 1994 to derive a catalogue of X-ray sources. The list contains 758 sources with their X-ray properties. From cross-correlations of the PSPC catalogue with the SIMBAD data base and literature searches we give likely identifications for 144 X-ray sources based on positional coincidence, but taking into account X-ray properties like hardness ratios and source extent. 46 known sources are associated with supernova remnants (SNRs) and candidates in the LMC, most of them already detected by previous X-ray missions. Including the new candidates from Haberl & Pietsch (1999) based on variability studies of the sources in our PSPC catalogue, the number of X-ray binaries in the LMC increased to 17 and that of the supersoft sources (SSSs) to 9. The remaining ~50% of the identified sources comprise mainly foreground stars (up to 57) and background extragalactic objects (up to 15). The often distinguished X-ray properties of the different source types were used for a first classification of new, unknown X-ray sources. Eight new PSPC sources are classified as SNRs from their hardness ratios and one promising new SNR candidate with extended X-ray emission is found further north than all known SNRs. Three soft X-ray sources have hardness ratios compatible to those of the known SSSs. A selection on hardness ratios and X-ray to optical flux ratio further suggests 27 foreground stars and 3 AGN.