Night-to-night variability of the emission lines in the spectrum of the Seyfert galaxy NGC 3227 nucleus

摘要

This is a study of optical emission lines of the nucleus of the Seyfert galaxy NGC 3227. This work is based on 53 spectrograms obtained with the 6-m telescope at the brightness maximum of this galactic nucleus on January 12-15, 1977. A set of profiles of the hydrogen H-alpha, and H-beta lines and the equivalent widths (EW lambda) of six emission lines and blends averaged over series of observations are presented. Broadening of the hydrogen line profiles was observed over the three days. At a level of 0.50 times the peak brightness the hydrogen line profiles were broadened by 12%, 35%, and 44%, respectively. The broadening of the H-beta line was accompanied by a reduction in its equivalent width (EW beta). It is suggested that a flare was observed in the nucleus of the galaxy on a time scale of 3 days, possibly caused to a shock wave in long-lived flows from the galaxy nucleus.