2003MNRAS.345.1133M

We compute the virial mass (M) of the central black hole and the luminosity-to-mass (L/M) ratio of ~300 low-z quasars and luminous type 1 Seyfert nuclei. We analyse the following: (1) whether radio-quiet and radio-loud objects show systematic differences in terms of M and L/M; (2) the influence of M and L/M on the shape of the Hβ broad component line profile; and (3) the significance of the so-called `blue outliers', i.e. sources showing a significant blueshift of the [O III]λλ4959,5007 lines with respect to the narrow component of Hβ, which is used as an estimator of the quasar reference frame. We show that M and L/M distributions for radio-quiet and radio-loud sources are probably different for samples matched in luminosity and redshift, in the sense that radio-quiet sources have systematically smaller masses and larger L/M. However, the L/M ratio distributions become indistinguishable if 8.5 < logM < 9.5. Line profile comparisons for median spectra computed over narrow ranges of M and L/M indicate that a Lorentz function provides a better fit for higher L/M sources and a double Gaussian for lower L/M values. A second (redshifted) Gaussian component at low L/M appears as a red asymmetry frequently observed in radio-loud and radio-quiet sources with broader (full width at half-maximum ≳4000 km/s) Hβ broad component profiles. This component becomes stronger in larger mass and lower L/M sources. No specific influence of radio loudness on the Hβ broad component profile is detected, although equivalent widths of Hβ broad component and especially of [O III]λλ4959,5007 are larger for radio-loud sources. We identify five more `blue outlier' sources. Since these sources are, on average, one magnitude brighter than other active galactic nuclei with similar mass, their resulting Eddington ratio is 2-3 times higher. We hint at evolutionary effects that explain some of these results, and reinforce the `eigenvector 1' correlations.