The Origin Of The Active Galactic Nuclear CIV Wide Emission Line

AGNs/QSOs are the nuclei of the most active galaxies. Their physical prop-erties of structure and evolution are always the hot content in astronomy field.For a collected sample consisting of 87 Palomar Green (PG) QSOs with z< 0.5,44 Sloan Digital Sky Survey (SDSS) high - z QSOs with z > 2, 33 local AGNs and 9 Weak Line QSOs (WLQs), we investigate the origin of C Ⅳλ1549A broad emission line including the Baldwin effect, the physical driver relative to the supermassive black hole (SMBH) accretion and the blueshift.(1) According the two-dimensional surface brightness decompositions of Re-verberation mapping (RM) AGNs, an empirical formula of monochromatic lu-minosity of AλLλ(5100A) from AGNs is given and used to estimate the Hβ-based MBH and Lbol/LEdd from the single epoch spectra.(2) For PG QSOs and high -z QSOs, the UV spectrum is decomposed with two components, one with intermediate-width (narrow component, NC) and another with very broad width (broad component, BC). Through the uniform decomposition for C iv profile, we find a obvious correlation of Baldwin effect and the relationship between C Ⅳ equivalent width (EW) and Lbol/LEdd. The correlation coefficients are -0.65 and -0.68 respectively. The correlation coefficient for BC (r=-0.64) is slightly higher than NC (r=-0.56) for Baldwin effect. The correlation of BC (r=-0.67) for the relationship between EW (C IV) and Lbol/LEdd is also slightly higher than NC (r=-0.58). In addition, the EW of BC is bigger than that of NC. It indicates that the covering factor of inner of broad line regions may be bigger.(3) Considering the additional data from local AGNs and WLQs, the Bald-win effect and its physic driver across a wider parameter range of Lbol/LEdd are investigated. Some AGNs with Lbol/LEdd less than -3 do not follow the anti-correlation between EW (C Ⅳ) and Lbol/LEdd. WLQs follow the anti-correlation between EW (C Ⅳ) and M. The different relationship between EW and Lbol/LEdd (M) support the point that broad line regions is formed due to the instability of accretion disk self-gravitation.(4) Considering the redshifts based on [O Ⅲ] or Hβ,it is confirmed that the blueshift is exists for high-ionization C Ⅳ broad emission lines by the com-posite spectrum. A medium strong negative relationship is found between the blueshift and EW (C Ⅳ) and a medium strong positive correlation is found be-tween blueshift and Lbol/LEdd. It indicates that the radiation pressure may be the driver of outflow. There is a medium strong correlation between the ratio of C iv-based MBH to Hβ -based MBH and the blueshiftof C Ⅳ, which indicates that the bias for C Ⅳ-based MBH is dominated by the outflow.