The X-ray view of M 33 after ROSAT*
Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
Corresponding author: F. Haberl, firstname.lastname@example.org
Accepted: 14 April 2001
We present a catalogue of 184 X-ray sources within 50´of the nucleus of the local group spiral galaxy M 33. The catalogue is derived from an analysis of the complete set of ROSAT archival data pointed in the direction of M 33 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 M 33. 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.
Key words: galaxies: individual: Messier 33 / galaxies: stellar content / stars: variables: general / X-rays: stars / catalogs
© ESO, 2001