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S.C. Gallagher (UCLA), G.T. Richards (Princeton), P.B. Hall (Princeton, York), D.P. Schneider, W.N. Brandt (Penn State), D.E. Vanden Berk (University of Pittsburgh)
We present Chandra observations of six bright quasars that represent extrema in quasar emission-line properties --- three quasars each with small and large blueshifts of the CIV emission line with respect to the systemic redshift of the quasars. Supplemented with seven archival Chandra observations of quasars that met our selection criteria, we investigate the origin of this emission-line phenomenon in the general context of the structure of quasars. We find that the quasars with the most extreme CIV blueshifts show significant evidence for intrinsic X-ray absorption from joint-spectral fitting that supports a wind origin for the emission-line shift. Furthermore, we find a significant correlation of delta(g-i), the redshift-corrected observed optical continuum color, with the X-ray hardness ratio such that intrinsically redder quasars have harder 0.5-8.0 keV spectra. In conjunction with evidence from joint-spectral fitting, this result points to intrinsically red quasars having systematically flatter hard X-ray continua without evidence for X-ray absorption. We speculate on the origins of the correlations of X-ray properties with both CIV blueshift and delta(g-i) and discuss the implications for models of quasar structure.
We acknowledge support from NASA and the Chandra X-ray Center.
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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.