Spectral optical monitoring of the double peaked emission line AGN Arp
  102B: II. Variability of the broad line properties
  We investigate a long-term (26 years, from 1987 to 2013) variability in the
broad spectral line properties of the radio galaxy Arp 102B, an active galaxy
with broad double-peaked emission lines. We use observations presented in Paper
I (Shapovalova et al. 2013) in the period from 1987 to 2011, and a new set of
observations performed in 2012--2013. To explore the BLR geometry, and clarify
some contradictions about the nature of the BLR in Arp 102B we explore
variations in the H$\alpha$ and H$\beta$ line parameters during the monitored
period. We fit the broad lines with three broad Gaussian functions finding the
positions and intensities of the blue and red peaks in H$\alpha$ and H$\beta$.
Additionally we fit averaged line profiles with the disc model. We find that
the broad line profiles are double-peaked and have not been changed
significantly in shapes, beside an additional small peak that, from time to
time can be seen in the blue part of the H$\alpha$ line. The positions of the
blue and red peaks { have not changed significantly during the monitored
period. The H$\beta$ line is broader than H$\alpha$ line in the monitored
period. The disc model is able to reproduce the H$\beta$ and H$\alpha$ broad
line profiles, however, observed variability in the line parameters are not in
a good agreement with the emission disc hypothesis. It seems that the BLR of
Arp 102B has a disc-like geometry, but the role of an outflow can also play an
important role in observed variation of the broad line properties.
