On the iron Kalpha complex in magnetic cataclysmic variables

Abstract

We present a compilation of spectra of the iron Kalpha region in magnetic cataclysmic variables, using data from the Chandra-HETG. The H-like, He-like and fluorescent components are clearly resolved, and there are hints of the structure within each component. The different shape of the He-like component in AM Her might be related to greater cyclotron cooling in this star. A surprising absence of Doppler shifts in the H-like and He-like components implies that the X-ray emission is predominantly from the denser, lower-velocity base of the accretion columns. This absence will allow ASTRO-E2 to resolve the structure in each component, leading to temperature diagnostics. We do not confirm the report that the H-like and He-like components of AO Psc are Compton broadened; however we do detect a Compton-downshifted shoulder to the fluorescent line of GK Per. Further, a Doppler-shifted wing of this line arises in the high-velocity, pre-shock flow.