HINTS ON THE BROAD LINE REGION STRUCTURE OF QUASARS AT HIGH AND LOW LUMINOSITIES

摘要

Quasars show a considerable spectroscopic diversity. However, the variety of quasar spectra at low redshifts is non-random: a principal component analysis applied to large samples customarily identifies two main eigenvectors. In this contribution we show that the range of quasar optical spectral properties observed at low-z and associated with the first eigenvector is preserved up to z ≈2 in a sample of high luminosity quasars. We also describe two major luminosity effects.