The UV spectra of intermediate redshift quasars.

A sample of 21 intermediate redshift quasars were observed with the IUE in order to study their line and continuum properties. In addition, 18 of the quasars were observed by the Einstein observatory. These measurements allow study of the ionizing continuum and the anomalous L_alpha/H sub beta ratio in a well defined sample of quasars. The data also allow determination of the percentage of the quasar continuum that is covered by gas clouds. The main results are: (1) the mean UV slope for this sample is -0.99 + or - 0.11; (2) the mean slope from 1200 A to 2 keV is -1.45 + or - 0.03; (3) two thirds of the objects have UV slopes that extrapolate to more than two sigma above the X-ray flux; (4) for 11 objects, the mean L_alpha/H sub beta ratio is 8.3 + or - 1.4; and (5) the covering factor is estimated to be about 0.17.