ROSAT X-ray analysis of the AM Her cataclysmic variable VV Pup

Abstract

VVPup is a typical AMHer-type system of stars, where the main accreting pole rotates in and out of view during the orbital cycle. The ROSAT data analysis for the magnetic cataclysmic variable VVPup is presented, and the x-ray light curves in a high state are obtained. The mean best-fit PSPC spectrum covering all the phase intervals is calculated. The shape of the light curve is in good agreement with both the optical and the EUV light curves. Also, the spectral parameters, the hardness ratios, the count rate, and the total integrated blackbody flux are studied. The results show that the flux tends to be softer when the source is in the bright phase, and becomes harder when it is close to the horizon of the white dwarf. A strong correlation between the blackbody temperature and the hydrogen column density is found at different confidence levels.