Extending the Eigenvector 1 Space to the Optical Variability of Quasars

Abstract

We introduce a new physical parameter, the optical variability amplitude, to the well-established Eigenvector 1 space of quasars and test a sample of long-term Bband light curves of 42 Palomar-Green quasars monitored by Giveon et al. We find that the optical variability amplitude strongly correlates with the intensity ratio of FeII to Hβ, Hβ width and peak luminosity at 5007 Å. We briefly discuss the physical meaning of our findings and suggest that the Eddington ratio may be a key factor in determining a quasar’s variability.