X-Rays from the Highly Polarized Broad Absorption Line QSO CSO 755

We present results from a BeppoSAX observation of the BAL QSO CSO 755,observed as part of our program to investigate the X-ray properties of highlypolarized BAL QSOs. CSO 755 is clearly detected by the BeppoSAX MECS, making itthe highest redshift (z=2.88) and most optically luminous (M_V=-27.4) BAL QSOseen in X-rays. It is detected in several energy bands including the rest-frame21-39 keV band, but we are only able to place loose constraints upon its X-rayspectral shape. Our X-ray detection is consistent with the hypothesis that theBAL QSOs with high optical continuum polarization tend to be the X-ray brightermembers of the class. We examine a scattering interpretation of apolarization/X-ray flux connection, and we discuss the data needed to prove orrefute such a connection. We also discuss a probable ROSAT detection of CSO755. The observed-frame 2-10 keV flux from BeppoSAX (1.3 x 10^{-13} erg cm^{-2}s^{-1}) is high enough to allow XMM spectroscopy, and studies of iron K lineemission should prove of particular interest if a large amount of scatteredX-ray flux is present.