The X-ray view of M33 after ROSAT

We present a catalogue of 184 X-ray sources within 50' of the nucleus of the local group spiral galaxy M33. The catalogue is derived from an analysis of the complete set of ROSAT archival data pointed in the direction of M33 and contains X-ray position, existence likelihood, count rates and PSPC spectral hardness ratios. To identify the sources the catalog was correlated with previous X-ray catalogues, optical and radio catalogues. In addition sources were classified according to their X-ray properties. We find seven candidates for supersoft X-ray sources, of which two may be associated with known planetary nebulae in M33. The majority of X-ray detected supernova remnants is also detected at radio frequencies and seen in optical lines. The low overall X-ray detection rate of optically selected SNRs can probably be attributed to their expansion into interstellar matter of low density.