First X-ray observations of the polar CE Gru

Abstract

We report the detection of the polar CE Gru in X-rays for the first time. We find evidence for a dip seen in the hard X-ray light curve which we attribute to the accretion stream obscuring the accretion region in the lower hemisphere of the white dwarf. The X-ray spectrum can be fitted using only a shock model: there is no distinct soft X-ray component. We suggest that this is because the reprocessed component is so cool that it is shifted into the ultraviolet. We determine a mass for the white dwarf of ~1.0 M_solar.