THE NATURE OF SOFT X-RAY WEAK QSOS

About 10% of the quasars can be classified as soft Xrayweak, whose Xrayemission is by a factor 1030 fainter than in typical quasars. They show astrong correlation between Alpha(OX) and the C IV absorption equivalent width,which suggest that absorption is the primary cause of their soft Xrayweakness. But the shape of the correlation can not be reproduced by an uniformscreen covering both the Xray source and the ultraviolet emission. Thereforeeither the UV and Xray absorbers are not identical (warm absorber, partlycovered, only scattered flux) or the Xray weakness is due to a peculiarproperty of the nuclear emission, as extreme variability or unusual steepness. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]