2008A&A...489.1121R

We measure the spatial distribution and hard X-ray luminosity function of cataclysmic variables (CVs) using the INTEGRAL all-sky survey in the 17-60keV energy band. The vast majority of CVs detected by INTEGRAL are intermediate polars of luminosity in the range 10³²-10³⁴erg/s. The scale height of the Galactic disk population of intermediate polars is found to be 130⁺⁹³_–46pc. The CV luminosity function measured with INTEGRAL in hard X-rays is compatible with that previously determined at lower energies (3-20keV) using a largely independent sample of sources detected by RXTE (located at |b|>10° as opposed to the INTEGRAL sample, which is strongly concentrated to the Galactic plane). The cumulative 17-60keV luminosity density of CVs per unit stellar mass is found to be (1.3±0.3)x10²⁷erg/s/M_☉, which is comparable to that of low-mass X-ray binaries in this energy band. Therefore, faint but numerous CVs are expected to provide an important contribution to the cumulative hard X-ray emission of galaxies.