Indicators of Black Hole Mass and Accretion Rate from QSOs UV Spectra

In a principal component analysis of the UV-optical spectra of an essentially complete sample of 22 optically-selected QSOs, we have found that most of the spectrum-tospectrum emission-line variance is contained in two sets of relationships - one, apparently driven by luminosity, representing the Baldwin effect, and the other apparently driven by Eddington accretion ratio, linking X-ray spectral index, broad emission-line width, and many relationships among broad UV and optical lines and [O III]5007, including inverse relationships of the strength of optical Fe II with UV Fe II blends and [O III]5007. The latter imply copious amounts of dense gas available to fuel the central engine. We will discuss the implications for the determination of black-hole masses of higher-redshift QSOs.