Sergyeyev S. Variability of the broad emission lines in active galactic nuclei

The broad-line region in active galactic nuclei has been studied. The primary goals of this study are determination of the BLR size and investigation of the relationship between the broad-line and continuum variations. The investigation methods are the spectral monitoring and analysis of AGN spectra. The BLR size has been measured for six AGNs. It was shown that the line-to-continuum dependence is not static, but variable. A model of independent flares has been proposed. The obtained results are widely used in many astronomical institutes, where the study of AGNs is carried out.