2013MNRAS.434.2664Z

In this paper, the properties of the proposed intermediate broad emission line region (BLR) are checked for the mapped AGN PG 0052+251. With the considerations of the apparent effects of the broad He ii line on the observed broad Hβ profile, the line parameters (especially the line width and the line flux) of the observed broad Hα and the broad Hβ are carefully determined. Based on the measured line parameters, the model with two broad components applied for each observed broad Balmer line is preferred, and then confirmed by the calculated much different time lags for the inner/intermediate broad components and the corresponding virial black hole mass ratio determined by the properties of the inner and the intermediate broad components. Then, the correlation between the broad line width and the broad line flux is checked for the two broad components: one clearly strong negative correlation for the inner broad component and one positive correlation for the intermediate broad component. The different correlations for the two broad components strongly support the intermediate BLR of PG 0052+251.