ИСТИНА

We present the results of long-term (1987–2013) optical spectral monitoring of the broad-line radio galaxy Arp 102B, a prototype of active galactic nucleus with double-peaked broad emission lines that are commonly assumed to be emitted from an accretion disk. We explore variations in the H-alpha and H-beta line parameters. The H-beta line was broader than H-alpha line during the monitored period. The broad line profiles are double-peaked showing no great (around 20%) changes beside an additional small peak detectable from time to time in the blue wing of the H-alpha line. We fit the broad lines with three broad Gaussian functions finding the positions and intensities of the blue and red peaks. The positions of the blue and red peaks stay almost unchanged (± 500 km s-1). A weak correlation between the line and continuum flux variation may evidence that the line variation is connected weakly with the variation of the central photoionization source. In spite of weak line-continuum correlation, we estimated a time lag for H-beta as of about 20 days and the central black hole mass as of about 1.1 10^8 mass of the Sun. We fitted averaged line profiles with the disc model and found no good agreement. It seems that the BLR of Arp 102B has a disc-like geometry, but an outflow can also play an important role in observed variation of the broad line properties.