AAS 198th Meeting, June 2001
Session 79. Galaxy Surveys
Oral, Thursday, June 7, 2001, 10:00-11:30am, C106

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[79.07] Iron Evolution Detected in a Large Uniform Quasar Sample

K. Forster, P.J. Green, J. Kuraszkiewicz (Harvard-Smithsonian CfA)

From a large homogeneous sample of optical/UV emission line measurements for 993 quasars from the Large Bright Quasar Survey (LBQS), our semi-automated spectral fitting detects many correlations. A new finding is a significant Baldwin Effect in UV iron emission. Further analysis reveals that the primary correlation of iron emission strength is probably with redshift, implying an evolutionary rather than a luminosity effect. We show that for most emission lines with a significant Baldwin Effect, and for some without, evolution dominates over luminosity effects. This may reflect evolution in abundances, in cloud covering factors, or overall cloud conditions such as density and ionization. Upcoming uniform measurements of other large quasar samples will extend the luminosity and redshift range of such spectral studies and provide even stronger tests of spectral evolution.

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