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The complete set of ASCA X-ray observations of non-magnetic cataclysmic variables |
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| Authors: | Darren S Baskill Peter J Wheatley Julian P Osborne |
| Institution: | Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH |
| Abstract: | We present the complete set of 34 ASCA observations of non-magnetic cataclysmic variables. Timing analysis reveals large X-ray flux variations in dwarf novae in outburst (Z Cam, SS Cyg and SU UMa) and orbital modulation in high inclination systems (including OY Car, HT Cas, U Gem, T Leo). We also found episodes of unusually low accretion rate during quiescence (VW Hyi and SS Cyg). Spectral analysis reveals broad temperature distributions in individual systems, with emission weighted to lower temperatures in dwarf novae in outburst. Absorption in excess of interstellar values is required in dwarf novae in outburst, but not in quiescence. We also find evidence for subsolar abundances and X-ray reflection in the brightest systems. LS Peg, V426 Oph and EI UMa have X-ray spectra that are distinct from the rest of the sample and all three exhibit candidate X-ray periodicities. We argue that they should be reclassified as intermediate polars. In the case of V345 Pav we found that the X-ray source had been previously misidentified. |
| Keywords: | stars: dwarf novae novae cataclysmic variables X-rays: stars |