Constraining the accretion geometry of the intermediate polar EX Hya using NuSTAR, Swift and Chandra observations
arXiv:1711.03942 · doi:10.3847/2041-8213/aaa28f
Abstract
In magnetically accreting white dwarfs, the height above the white dwarf surface where the standing shock is formed is intimately related with the accretion rate and the white dwarf mass. However, it is difficult to measure. We obtained new data with NuSTAR and Swift that, together with archival Chandra data, allow us to constrain the height of the shock in the intermediate polar EX Hya. We conclude that the shock has to form at least at a distance of about one white dwarf radius from the surface in order to explain the weak Fe Kα 6.4 keV line, the absence of a reflection hump in the high-energy continuum, and the energy dependence of the white dwarf spin pulsed fraction. Additionally, the NuSTAR data allowed us to measure the true, uncontaminated hard X-ray (12-40 keV) flux, whose measurement was contaminated by the nearby galaxy cluster Abell 3528 in non-imaging X-ray instruments.
accepted version after referee comments
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Cited by in corpus (10)
- Hard X-ray view on intermediate polars in the Gaia era
- Hard X-ray Cataclysmic Variables
- Measuring the masses of magnetic white dwarfs: A NuSTAR Legacy Survey
- The multi-wavelength view of shocks in the fastest nova V1674 Her
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- Breaking the degeneracy in magnetic cataclysmic variable X-ray spectral modeling using X-ray light curves
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