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A. E. Bauer (Cincinnati), D. E. Vanden Berk (Fermilab), G. T. Richards, D. P. Schneider (Penn State), M. A. Strauss (Princeton), F. Xiaohui (IAS), D. G. York (Chicago)
We present a variety of composite quasar spectra using a data set of over 4500 optical, radio, and x-ray selected spectra from the Sloan Digital Sky Survey (SDSS). The composite spectra span a rest-frame wavelength range of 800-8555 Angstroms, at a resolution of \approx 1800. We examine global composite spectral characteristics for numerous quasar subsamples classified by redshift, luminosity, x-ray and radio detection, and the presence of broad absorption line (BAL) systems. We find only a marginal reddening of the spectral slope with redshift, except that the lowest redshift quasars show significant host galaxy contamination at long wavelengths. Radio detected quasars are slightly redder, have broader H-alpha lines, narrower MgII lines, and weaker forbidden lines than quasars with no radio detection. X-ray detected quasars are slightly bluer at long wavelengths, and have stronger CIV, MgII, H-beta, and [OIII] lines than quasars without x-ray detections. As luminosity increases, quasars become bluer at short wavelengths and CIII] broadens. Broad absorption line quasars in general are significantly redder than those without BAL systems, and low-ionization BAL quasars are redder still.
The Sloan Digital Sky Survey (SDSS) is a joint project of The University of Chicago, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Princeton University, the United States Naval Observatory, and the University of Washington. Apache Point Observatory, site of the SDSS telescopes, is operated by the Astrophysical Research Consortium (ARC).
Funding for the project has been provided by the Alfred P. Sloan Foundation, the SDSS member institutions, the National Aeronautics and Space Administration, the National Science Foundation, the U.S. Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. The SDSS Web site is http://www.sdss.org/.
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The author(s) of this abstract have provided an email address for comments about the abstract: abauer@physics.uc.edu