Line shape variability in a sample of AGN with broad lines
  The spectral variability of active galactic nuclei (AGN) is one of their key
features that enables us to study in more details the structure of AGN emitting
regions. Especially, the broad line profiles, that vary both in flux and shape,
give us invaluable information about the kinematics and geometry of the broad
line region (BLR) where these lines are originating from. We give here a
comparative review of the line shape variability in a sample of five type 1
AGN, those with broad emission lines in their spectra, of the data obtained
from the international long-term optical monitoring campaign coordinated by the
Special Astrophysical Observatory of the Russian Academy of Science. The main
aim of this campaign is to study the physics and kinematics of the BLR on a
uniform data set, focusing on the problems of the photoionization heating of
the BLR and its geometry, where in this paper we give for a first time a
comparative analysis of the variabilty of five type 1 AGN, discussing their
complex BLR physics and geometry in the framework of the estimates of the
supermassive black hole mass in AGN.
