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A. van Teeseling, J.J. Drake, J.E. Drew, M.G. Hoare, and F. Verbunt
We have obtained ROSAT PSPC and EUVE DSS observations of the nova-like variable IX Vel. The ROSAT data show irregular variations on time scales ranging from 50s to a month. The X-ray flux varies with an amplitude of 15-20% on the orbital period, mainly due to variation in emission measure, and reaching minimum when the white dwarf is closest to Earth. The EUV and X-ray flux can be modelled with a single optically thin spectrum. Its bolometric flux is much less than the optical and ultraviolet flux of the accretion disk. Orbital and long-term variations are also found in the EUVE data, and have a larger amplitude than the X-ray variations. This can be explained with variations in absorption column on these time scales. In the X-ray data there is significant spectral variability, in part due to a variable absorption column, which yields a complex relation between the X-ray count rate and hardness ratio. The origin of the X-rays in IX Vel is discussed and we are forced to conclude that there is as yet no satisfactory explanation for the observed orbital modulation in the X-ray flux.
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