南方基地知识库

Using a high-luminosity (L-bol similar to 10(47.5)-10(48.3)erg s(-1)), high-redshift (3.2 z < 3.8) quasar sample of 19 quasars with optical and near-infrared spectroscopy, we investigate the reliability of the Civ-based black hole mass estimates (M-BH). The median logarithm of the Civ- and H beta-basedM(BH)ratios is 0.110 dex, with a scatter of 0.647 dex. The Civ-to-H beta BH mass differences are significantly correlated with the CivFWHMs, blueshifts, and asymmetries. Corrections of the CivFWHM using the blueshift and asymmetry reduce the scatter of the mass differences by similar to 0.04-0.2 dex. Quasars in our sample accrete at the Eddington ratioR(EDD) > 0.3 and cover a considerable range of blueshifts, with 18/19 of the quasars showing Civblueshifts (with the median value of 1126 km s(-1)) and 14/19 of the quasars showing Civblueshifts larger than 500 km s(-1). It suggests that not all quasars with high Eddington ratios show large blueshifts. The Baldwin effect between the Civrest-frame equivalent width (REW) and the continuum luminosity at 1350 A is not seen, likely due to the limited luminosity range of our sample. We find a lack of flux in the red wing of the composite spectrum with larger Civblueshift and detect a higher ratio of [Oiii] quasars with REW[Oiii] > 5 A in the subsample with lower Civblueshift. It is more likely that they are caused by the combination of the Eddington ratio and the orientation effect.