Hard X-ray surveys have proven remarkably efficient in detecting intermediate polars and asynchronous polars , two of the rarest type of cataclysmic variable ( CV ) .
Here we present a global study of hard X-ray selected intermediate polars and asynchronous polars , focusing particularly on the link between hard X-ray properties and spin/orbital periods .
To this end , we first construct a new sample of these objects by cross-correlating candidate sources detected in INTEGRAL /IBIS observations against catalogues of known CVs .
We find 23 cataclysmic variable matches , and also present an additional 9 ( of which 3 are definite ) likely magnetic cataclysmic variables ( mCVs ) identified by others through optical follow-ups of IBIS detections .
We also include in our analysis hard X-ray observations from Swift /BAT and SUZAKU /HXD in order to make our study more complete .
We find that most hard X-ray detected mCVs have P _ { spin } / P _ { orb } < 0.1 above the period gap .
In this respect we also point out the very low number of detected systems in any band between P _ { spin } / P _ { orb } = 0.3 and P _ { spin } / P _ { orb } = 1 and the apparent peak of the P _ { spin } / P _ { orb } distribution at about 0.1 .
The observational features of the P _ { spin } - P _ { orb } plane are discussed in the context of mCV evolution scenarios .
We also present for the first time evidence for correlations between hard X-ray spectral hardness and P _ { spin } , P _ { orb } and P _ { spin } / P _ { orb } .
An attempt to explain the observed correlations is made in the context of mCV evolution and accretion footprint geometries on the white dwarf surface .