A HIGH SIGNAL-TO-NOISE RATIO COMPOSITE QUASAR SPECTRUM

We present a very high signal-to-noise ratio (S/N approximately 400) composite spectrum of the rest-frame ultraviolet and optical region of high luminosity quasars. The spectrum is derived from 718 individual spectra obtained as part of the Large Bright Quasar Survey. The moderate resolution, less-than-or-similar-to 4 angstrom, and high signal-to-noise ratio allow numerous weak emission features to be identified. Of particular note is the large equivalent-width of the Fe II emission in the rest-frame ultraviolet and the blue continuum slope of the composite. The primary aim of this paper is to provide a reference spectrum for use in line identifications, and a series of large-scale representations of the composite spectrum are shown. We also present a measure of the standard deviation of the individual quasar spectra from the composite spectrum.