Astron. Astrophys. Suppl. Ser. 143, 391-403
ROSAT HRI catalogue of X-ray sources in the LMC
M. Sasaki - F. Haberl - W. Pietsch
Send offprint request: M. Sasaki,
Max-Planck-Institut für extraterrestrische Physik,
Giessenbachstraße, D-85748 Garching, Germany
Received December 30, 1999; accepted January 20, 2000
All 543 pointed observations of the ROSAT High Resolution Imager (HRI)
with exposure times higher than 50 s
and performed between 1990 and 1998 in a field of 10
covering the Large Magellanic Cloud (LMC) were analyzed.
A catalogue was produced containing 397 X-ray sources with
their properties measured by the HRI. The list was cross-correlated
with the ROSAT Position Sensitive Propotional
Counter (PSPC) source catalogue presented by Haberl & Pietsch (1999)
in order to obtain the hardness ratios for the X-ray sources detected
by both instruments. 138 HRI sources are contained in the PSPC
catalogue, 259 sources are new detections.
The spatial resolution of the HRI was
higher than that of the PSPC and the source position could be
determined with errors mostly smaller than 15
dominated by systematic attitude errors.
After cross-correlating the source catalogue with the SIMBAD data base
and the TYCHO catalogue 94 HRI sources were identified with
known objects based on their positional coincidence and X-ray
properties. Whenever more accurate coordinates were given in
catalogues or literature for identified sources, the X-ray coordinates
were corrected and the systematic error of the X-ray position was
reduced. For other sources observed simultaneously with an identified
source the coordinates were improved as well.
In total the X-ray position of 254 sources could be newly determined.
The catalogue contains 39 foreground stars, 24 supernova remnants
(SNRs), five supersoft sources (SSSs), nine X-ray binaries (XBs), and
nine AGN well known from literature. Another eight sources
were identified with known candidates for these source classes.
Additional 21 HRI sources are suggested in the present work as
candidates for SNR, X-ray binary in the LMC, or background AGN
because of their extent, hardness ratios, X-ray to optical flux ratio,
or flux variability.
Key words: catalogues -- galaxies: Magellanic Clouds --
galaxies: stellar content --
X-rays: galaxies -- X-rays: stars
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