Study of Outflows in Luminous Quasars at Redshift ∼0.4–0.8

We perform a systematic study of outflow in the narrow-line region (NLR) of active galactic nuclei (AGNs) at z similar to 0.4-0.8 based upon a large sample of similar to 900 quasars at z similar to 0.4-0.8. The sample is extracted from the Sloan Digital Sky Survey by mainly requiring that (1) the g-band magnitude is brighter than 19 mag and (2) the [O III]lambda 5007 emission line has a signal-to-noise ratio larger than 30. Profiles of multiple emission lines are modeled by a sum of several Gaussian functions. The spectral analysis allows us to identify (1) a prevalence of both [O III]lambda 5007 line blue asymmetry and bulk velocity blueshift of both [Ne III]lambda 3869 and [Ne III]lambda 3426 lines, when the [O II]lambda 3727 line is used as a reference. The velocity offset of the [O III]lambda 5007 line is, however, distributed around a value of zero, except for a few outliers. (2) Not only the significant [O III]lambda 5007 line asymmetry, but also the large bulk velocity offsets of [Ne III]lambda 3869 and [Ne V]lambda 3426 emission lines tend to occur in the objects with high L/L-Edd, which is considerably consistent with the conclusions based on local AGNs. With three M-BH estimation methods, the significance level of the trend is found to be better than 2.9 sigma, 3.2 sigma, and 1.8 sigma for [O III], [Ne III], and [Ne V], respectively. After excluding the role of radio jets, the revealed dependence of NLR gas outflow on L/L-Edd allows us to argue that the pressure caused by the wind/radiation launched/emitted from a central supermassive black hole is the most likely origin of the outflow in these distant quasars, which implies that the outflow in luminous AGNs up to z similar to 1 have the same origin.