Bibcode
Pietsch, W.; Haberl, F.; Sala, G.; Stiele, H.; Hornoch, K.; Riffeser, A.; Fliri, J.; Bender, R.; Bühler, S.; Burwitz, V.; Greiner, J.; Seitz, S.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 465, Issue 2, April II 2007, pp.375-392
Fecha de publicación:
4
2007
Revista
Número de citas
86
Número de citas referidas
73
Descripción
Context: Optical novae have recently been identified as the major class
of supersoft X-ray sources in M 31 based on ROSAT and early XMM-Newton
and Chandra observations. Aims: This paper reports on a search
for X-ray counterparts of optical novae in M 31 based on archival
Chandra HRC-I and ACIS-I as well as XMM-Newton observations of the
galaxy center region obtained from July 2004 to February 2005. Methods: We systematically determine X-ray brightness or upper limit
for counterparts of all known optical novae with outbursts between
November 2003 to the end of the X-ray coverage. In addition, we
determine the X-ray brightnesses for counterparts of four novae with
earlier outbursts. Results: For comparison with the X-ray data we
created a catalogue of optical novae in M 31 based on our own nova
search programs and on all novae reported in the literature. We
collected all known properties and named the novae consistently
following the CBAT scheme. We detect eleven out of 34 novae within a
year after the optical outburst in X-rays. While for eleven novae we
detect the end of the supersoft source phase, seven novae are still
bright more than 1200, 1600, 1950, 2650, 3100, 3370 and 3380 d after
outburst. One nova is detected to turn on 50 d, another 200 d after
outburst. Three novae unexpectedly showed short X-ray outbursts starting
within 50 d after the optical outburst and lasting only two to three
months. The X-ray emission of several of the novae can be characterized
as supersoft from hardness ratios and/or X-ray spectra or by comparing
HRC-I count rates with ACIS-I count rates or upper limits. Conclusions: .The number of detected optical novae at supersoft X-rays
is much higher than previously estimated (>30%). We use the X-ray
light curves to estimate the burned masses of the White Dwarf and of the
ejecta.
Partly based on observations obtained with the Wendelstein Observatory
of the Universitätssternwarte München. Appendices are only
available in electronic form at http://www.aanda.org Tables A.1, A.2 and
B.2 are only available in electronic form at the CDS via anonymous ftp
to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/465/375