Quasar variability: Correlations with amplitude

The relation between quasar variability and parameters such as luminosity a nd redshift has been a matter of hot debate over the last few years with ma ny papers on the subject. Ally correlations which can be established will h ave a profound effect on models of quasar structure and evolution. The samp le of quasars with redshifts in ESO/SERC field 287 contains over 600 quasar s in the range 0 < z < 3.5 and is now large enough to bin in luminosity and redshift, and give definitive measures of the correlations. We find no sig nificant correlation between amplitude and redshift, except perhaps at very low redshift, but an inverse correlation between amplitude and luminosity. This is examined in the context of various models for quasar variability.