2006MNRAS.372..876B

We apply the stellar population synthesis code by Cid Fernandes et al. to model the stellar contribution for a sample of 209 type II active galactic nuclei (AGNs) at 0.3 < z < 0.83 from the Sloan Digital Sky Survey. The reliable stellar velocity dispersions (σ_*) are obtained for 33 type II AGNs with significant stellar absorption features. According to the L_[OIII]criterion of 3x10⁸L_☉, 20 of which can be classified as type II quasars. We use the formula of Greene and Ho to obtain the corrected stellar velocity dispersions (σ^c_*). We also calculate the supermassive black hole masses from σ^c_*in these high-redshift type II AGNs. The [Oiii] luminosity is correlated with the black hole mass (although no correlation between the extinction-corrected [Oiii] luminosity and the black hole mass), and no correlation is found between the Eddington ratio and the [Oiii] luminosity or the corrected [Oiii] luminosity. Three sets of two-component profiles are used to fit multiple emission transitions ([Oiii]λλ4959, 5007 and [Oii]λλ3727, 3729) in these 33 stellar-light-subtracted spectra. We also measure the gas velocity dispersion (σ_g) from these multiple transitions, and find that the relation between σ_gand σ^c_*becomes much weaker at higher redshifts than in smaller redshifts. The distribution of <σ_g/σ^c_*> is 1.24±0.76 for the core [Oiii] line and 1.20±0.96 for the [Oii] line, which suggests that σ_gof the core [Oiii] and [Oii] lines can trace σ^c_* within about 0.1 dex in the logarithm of σ^c_*. For the secondary driver, we find that the deviation of σ_gfrom σ^c_*is correlated with the Eddington ratio.