Nuclear activity of the Seyfert galaxy NGC 7469 in 1990-2006: Observations from the Mt. Maidanak Observatory

We present the results of UBV RI observations of the nucleus of the Seyfert 1 galaxy NGC 7469 performed in 1990-2006 at the Mt. Maidanak Observatory of the Ulug Beg Astronomical Institute in Uzbekistan. Light curves for various apertures are plotted for all the filters. Our analysis of these light curves indicates the presence of short-time-scale (from several days to several weeks) and long-term (similar to 8-9 years) variability of the nucleus. The character of the brightness variations in all the optical filters is the same, with the relative amplitude of the variations decreasing from U to V, but being higher in R than in V. A comparison with earlier observations (prior to 1990) indicates an increase of the time scale for the long-term variability, from three to six years to eight to nine years, providing evidence for changing emission conditions in the accretion disk. We present the results of a statistical analysis of the light curves and an analysis of the color characteristics during different activity periods. Color-index measurements using various apertures demonstrate that the color becomes bluer towards the galaxy nucleus.