Emission line & R-band continuum LCs of 17 QSOs

We are able to measure statistically significant lags for Ly{alpha} (11 objects), Si IV (5 objects), C IV (11 objects), and C III] (2 objects). Using our results and previous lag determinations taken from the literature, we present an updated C IV radius-luminosity relation and provide for the first time radius-luminosity relations for Ly{alpha}, Si IV, and C III].

While in all cases the slopes of the correlations are statistically significant, the zero points are poorly constrained because of the lack of data at the low- luminosity end. We find that the emissivity-weighted distances from the central source of the Ly{alpha}, Si IV, and C III] line-emitting regions are all similar, which corresponds to about half that of the H{beta} region. We also find that 3/17 of our sources show an unexpected behavior in some emission lines, two in the Ly{alpha} light curve and one in the Si IV light curve, in that they do not seem to follow the variability of the UV continuum.