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D. Pandel (UC Santa Barbara), F.A. Cordova, S.B. Howell (IGPP, UC Riverside)
We present our analysis of XMM-Newton data of the dwarf nova VW Hyi obtained during the quiescent state. The X-ray spectrum indicates that the boundary layer is an optically thin plasma with a continuous temperature distribution and a maximum temperature of ~6 keV. The ratio of boundary layer to disk luminosity is fairly low at 0.2. We find that the boundary layer is rotating at a velocity of ~600 km/s, which is similar to the white dwarf's rotation velocity. We detect a 60-s quasi-periodic X-ray oscillation that is possibly connected to the rotation of the boundary layer. A correlation is found between the X-ray and the ultra-violet variability with the X-rays being delayed by ~100 s. An orbital modulation of the X-ray flux suggests a misalignment between the rotation axes of the white dwarf and the inner disk.
Bulletin of the American Astronomical Society,
© 2003. The American Astronomical Soceity.