Diagnostics of the structure of AGN's broad line regions with reverberation mapping data: confirmation of the two-component broad line region model

摘要

We re-examine the ten Reverberation Mapping (RM) sources with public databased on the two-component model of the Broad Line Region (BLR). In fittingtheir broad H-beta lines, six of them only need one Gaussian component, one ofthem has a double-peak profile, one has an irregular profile, and only two ofthem need two components, i.e., a Very Broad Gaussian Component (VBGC) and anInter-Mediate Gaussian Component (IMGC). The Gaussian components are assumed tocome from two distinct regions in the two-component model; they are Very BroadLine Region (VBLR) and Inter-Mediate Line region (IMLR). The two sources with atwo-component profile are Mrk 509 and NGC 4051. The time lags of the twocomponents of both sources satisfy $t_{IMLR}/t_{VBLR}=V^2_{VBLR}/V^2_{IMLR}$,where $t_{IMLR}$ and $t_{VBLR}$ are the lags of the two components while$V_{IMLR}$ and $V_{VBLR}$ represent the mean gas velocities of the two regions,supporting the two-component model of the BLR of Active Galactic Nuclei (AGN).The fact that most of these ten sources only have the VBGC confirms theassumption that RM mainly measures the radius of the VBLR; consequently, theradius obtained from the R-L relationship mainly represent the radius of VBLR.Moreover, NGC 4051, with a lag of about 5 days in the one component model, isan outlier on the R-L relationship as shown in Kaspi et al. (2005); howeverthis problem disappears in our two-component model with lags of about 2 and 6days for the VBGC and IMGC, respectively.