Wills, Beverley J.Laor, A.Brotherton, M. S.Wills, D.Wilkes, BelindaFerland, G. J.Shang, Zhaohui2017-02-131999Wills, Beverley J., A. Laor, M. S. Brotherton, D. Wills, B. J. Wilkes, G. J. Ferland, and Zhaohui Shang. 1999. “The PG X-Ray QSO Sample: Links Between the Ultraviolet–X-Ray Continuum and Emission Lines.” The Astrophysical Journal 515 (2) (April 20): L53–L56. doi:10.1086/311980.0004-637Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:30212160Two sets of relationships relate QSO UV to soft X-ray continua with the broad-line region. These are (i) the Baldwin relationships, which are inverse relationships between the broad-line equivalent width and the continuum luminosity, and (ii) Boroson & Green's optical "Principal Component 1" relationships, linking steeper soft X-ray spectra with narrower Hβ emission, stronger Hβ blue wings, stronger optical Fe II emission, and weaker [O III] λ5007 lines. In order to understand these relationships, we extended the spectra into the UV for 22 QSOs with high-quality soft X-ray spectra. These are from the complete sample of QSOs from the Bright Quasar Survey for which Laor et al. demonstrated strong luminosity and X-ray-optical Principal Component 1 relationships. We show that these extend to a whole new set of UV relationships: Principal Component 1 (in the sense of steeper X-ray spectra) is related to narrower C III] λ1909 lines, larger Si III] λ1892/C III] λ1909 ratios (a high-density indicator), stronger low-ionization lines, and weaker C IV λ1549 but stronger N V λ1240 lines. We speculate that high accretion rates are linked to high columns of dense (~1011 cm−3), nitrogen-enhanced, low-ionization gas from nuclear starbursts. Line width, inverse Fe II-[O III] and inverse Fe II-C IV relationships hint at the geometrical arrangement of this gas. These Principal Component 1 relationships appear to be independent of luminosity and therefore of the Baldwin relationships.en-USAccretion, accretion disksGalaxies: starburstQuasars: emission linesQuasars: generalUltraviolet: galaxiesX-rays: galaxiesJournal Article2017-02-1310.1086/311980