The binaries known as cataclysmic variables are particular binary systems in which the primary star (a white dwarf) accretes material from a secondary via Roche-lobe mechanism. Usually, these objects have orbital period of a few hours so that a detailed temporal analysis can be performed. Here, we present Chandra and XMM-Newton observations of a dwarf nova candidate identified in the past by optical observations towards the galactic Bulge and labeled as MACHO 104.20906.960. After a spectral analysis, we used the Lomb-Scargle technique for the period search and evaluated the confidence level using Monte-Carlo simulations. In this case, we found that the X-ray source shows a period of 2:03þ0:09 0:07 h (3r error) so that it is most likely a system of interacting objects. The modulation of the signal was found with a confidence level of > 99%. The spectrum can be described by a two thermal plasma components with X-ray flux in the 0.3–10 keV energy band of 10^13 erg s^-1 cm^-2. We find that the distance of the source is approximately 1 kpc thus corresponding to a luminosity LX 2 x 10^31 erg s^-1.
A serendipitous XMM-Newton observation of MACHO 104.20906.960: a dwarf nova candidate with a 2h period
NUCITA, Achille;DE PAOLIS, Francesco;INGROSSO, Gabriele;MAIOLO, BERLINDA MARIA TERESA;
2009-01-01
Abstract
The binaries known as cataclysmic variables are particular binary systems in which the primary star (a white dwarf) accretes material from a secondary via Roche-lobe mechanism. Usually, these objects have orbital period of a few hours so that a detailed temporal analysis can be performed. Here, we present Chandra and XMM-Newton observations of a dwarf nova candidate identified in the past by optical observations towards the galactic Bulge and labeled as MACHO 104.20906.960. After a spectral analysis, we used the Lomb-Scargle technique for the period search and evaluated the confidence level using Monte-Carlo simulations. In this case, we found that the X-ray source shows a period of 2:03þ0:09 0:07 h (3r error) so that it is most likely a system of interacting objects. The modulation of the signal was found with a confidence level of > 99%. The spectrum can be described by a two thermal plasma components with X-ray flux in the 0.3–10 keV energy band of 10^13 erg s^-1 cm^-2. We find that the distance of the source is approximately 1 kpc thus corresponding to a luminosity LX 2 x 10^31 erg s^-1.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
