089062

The hard X-rays from accreting white dwarfs (WDs) in magnetic cataclysmic variables (CVs) are produced by shock-heating in the accretion column and the measured temperature of the accreting material depends on the mass of the WD. With high-quality hard X-ray spectra it is possible to determine the WD mass. An important question is whether the WD mass distribution extends up to the Chandrasekhar limit. The best place to look for high-mass WDs is among CVs with the hardest spectra making CVs found in the hard X-ray INTEGRAL survey excellent candidates for having the most massive WDs. We propose NuSTAR and XMM observations of two IGR CVs. In addition to measuring the WD masses the observations will be used to search for periodic signals expected to be seen at the WD rotation period. [truncated! Please see actual data for full text]