Emission Lines and the Spectral Energy Distributions of Quasars.

Many years of study have failed to conclusively establish relations between a quasar’s spectral energy distribution (SED) and the emission lines it is thought to produce. This is at least partially due to the lack of well-observed SEDs. We present initial results from a line– SED study for a sample of 43 quasars and active galaxies for which we have optical and ultra-violet spectra and far-infrared–X-ray SEDs. We present the results of tests for correlations between line equivalent widths and SED luminosity and slope parameters and compare these results to those from earlier studies. We find that the Baldwin effect is weaker when the luminosity is defined close to the ionising continuum of that line and conclude that the detailed SED is likely to be important in making further progress.