OPTICALLY LUMINOUS QSOS OBSERVED WITH ROSAT

We present ROSAT PSPC observations of six luminous high-redshift (z = 2.15 to 3.2) QSOs. All were detected in X-rays. For four of them with greater than or similar to 200 counts spectral fittings using power la ws yield a photon index alpha(P) = 2.25 +/- 0.2 acid hydrogen column d ensities NH consistent with Galactic NH values. There is no evidence f or excess absorption due to intervening matter, in agreement with Bech told et al.'s (1994) findings for radio quiet QSOs, who also found a s imilar spectral index. HE1104-1805 (z = 2.303), the recently discovere d bright double QSO (Wisotzki et al., 1993) is particularly X-ray loud (0.095 cts s(-1)) and radio quiet (<0.18 mJy at 6 cm). Our observatio ns support the view that the apparent excess absorption found in sever al radio-loud high redshift QSOs is intrinsic to the objects and disti nguishes them from radio quiet QSOs and from most low-redshift AGN whi ch have no intrinsic absorption.