Discovery of Associated Absorption Lines in an X-Ray Warm Absorber: HST-FOS Observations of MR2251-178

E. M. Monier, S. Mathur, B. Wilkes +1

The presence of a ``warm absorber'' was first suggested to explain spectral variability in an X-ray spectrum of the radio-quiet QSO MR2251-178. A unified picture, in which X-ray wa…