The virial factor $f$ of the H${\hat{I}}^2$ Broad-line for NGC 5548 and NGC 4151

Shao-Jun Li, Xiang-Wei Ning, Yan-Song Ma +2

The variability of virial factor $f$ is investigated for two active galactic nucleus, NGC 5548 and NGC 4151, which had been previously reverberation mapped (RM) over 20 times in th…