1996A&A...307..137W

We combine ROSAT, Ginga, and EXOSAT observations to investigate the X-ray and extreme-ultraviolet fluxes of VW Hyi in quiescence and throughout an ordinary dwarf-nova outburst. We show that the quiescent spectrum is consistent with emission from material heated to ∼12keV and cooling through the X-ray band to temperatures below our sensitivity range. During outburst the X-ray flux is suppressed, and recovers only at the very end of the optical outburst. The recovery starts intermittently with ∼100% modulations on a timescale of about 200s. A very soft component is detectable only in the extreme ultraviolet, after outburst maximum, and disappears before the end of the optical outburst. The luminosity of this component is limited to less than that expected from the boundary layer. The late recovery of the hard X-ray flux indicates that this flux is regulated by processes occurring very close to the white dwarf.