Quasar variability: Correlations with amplitude

Abstract. The relation between quasar variability and parameters such as luminosity and redshift has been a matter of hot debate over the last few years with many papers on the subject. Any correlations which can be es-tablished will have a profound eect on models of quasar structure and evolution. The sample of quasars with red-shifts in ESO/SERC eld 287 contains over 600 quasars in the range 0 < z < 3:5 and is now large enough to bin in luminosity and redshift, and give denitive mea-sures of the correlations. We nd no signicant correla-tion between amplitude and redshift, except perhaps at very low redshift, but an inverse correlation between am-plitude and luminosity. This is examined in the context of various models for quasar variability. Key words: quasars: general 1