Key points are not available for this paper at this time.
We present optical and near-infrared (NIR) spectroscopic observations for a sample of 45 quasars at 6. 50 6. 5 from ground-based instruments. Its homogeneity and reproducibility make it ideally suited for several scientific goals, i. e. , the study of the quasar proximity zones and damping wings, the Ly forest, the intergalactic medium's metal content, as well as other properties such as the distribution of SMBH masses and Eddington ratios. Our composite spectrum is compared to others at both high and low-z from the literature, showing differences in the strengths of many emission lines, probably due to differences in luminosity among the samples, but a consistent continuum slope, which proves that the same spectral features are preserved in quasars at different redshift ranges.
Onorato et al. (Tue,) studied this question.