X-RAY OBSERVATIONS OF THE WARM ABSORBER IN NGC-3783

We present a high signal-to-noise ROSAT position sensitive proportiona l counter (PSPC) observation of the Seyfert 1 galaxy NGC 3783. The 0.1 -2.5 keV spectrum shows strong evidence for an absorption edge most li kely associated with O VII-VIII. Such a feature, which has now been de tected in a number of PSPC spectra (Nandra et al.; Nandra & Pounds; Tu rner et al.), is the signature of highly ionized material the so-calle d warm absorber, in the line of sight to the X-ray source. The result is strongly supported by analysis of previously unpublished Ginga data and reanalysis of a 1985 EXOSAT observation of NGC 3783. We show that the warm absorber is plausibly located at a radius less than or simil ar to 10(18) cm from the X-ray source, possibly in an outflowing wind.