Black hole masses in type II AGNs from the Sloan Digital Sky Survey

The stellar population synthesis method is used to model the stellar contribution for a sample of 209 type II AGNs at 0.3>z>0.83 from the Sloan Digital Sky Survey. The reliable stellar velocity dispersions are obtained for 33 type II AGNs with significant stellar absorption features. We use the formula of Greene & Ho to obtain the corrected stellar velocity dispersions (σ_*^c). 20 of which can be classified as type II quasars. The SMBHs masses and the Eddington ratios are calculated. We measure the gas velocity dispersion (σ_g) from NLRs, and find that the relation between σ_g and σ_*^c becomes much weaker at higher redshifts than at smaller redshifts. We find that the deviation of σ_g from σ_*^c is correlated with the Eddington ratio.