AAS 201st Meeting, January, 2003
Session 98. AGNs, Black Holes, and Quasars
Oral, Wednesday, January 8, 2003, 10:00-11:30am, 616-617

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[98.01] What Causes the Scatter in the Black Hole Mass vs. Velocity Dispersion Relation for AGNs?

T.A. Boroson (NOAO)

The SDSS Early Data Release provides an interesting sample with which to explore some of the correlations and relationships that have been noted before for the emission-line properties of QSOs. From the spectroscopic database we have extracted the spectra of 107 radio-quiet QSOs with z < 0.5 and S/N per resolution element greater than 15. Following the removal of the Fe II multiplets using the usual template technique, we have measured line intensity and width information for the emission lines in the H\beta-[O III] spectral region, including a parameter P5007, which is highly correlated with eigenvector 1, the set of emission-line correlations that emerged from the Boroson and Green (1992) study of the PG QSO sample.

This dataset allows us to reproduce the black hole mass vs. velocity dispersion relation, using the H\beta width and optical luminosity to derive the black hole mass, and using the [O III] \lambda5007 width as a surrogate for the stellar velocity dispersion. While the fit to this relationship is quite similar to that for non-active galaxies, there is a large scatter, exceeding observational errors. An analysis of this scatter in terms of the measured emission lines shows that the QSOs that have [O III] too wide for their calculated black hole mass tend to have higher luminosity, narrower H\beta, and come from the strong Fe II/weak [O III] end of the E1 sequence. Possible explanations of this include simple models in which some of the characteristics are determined by orientation.

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