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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Based on our UBVRI observations conducted at the Maidanak Observatory (Uzbekistan) and X-ray data from the RXTE satellite, we investigate the variability of the Seyfert Galaxy NGC 7469 over the period 1994–2015. Our analysis of the light curves indicates the presence of the short-term (from several days to several weeks) and long-term (~3-9 years) variability of the nucleus. We study the long-term variability represented by three slow components (1994-2001, 2003-2007, 2008-2015). The character of brightness variations in UBVRI optical bands is the same, with the relative amplitude of the variations decreasing from U to I. We present results of the statistical analysis of the light curves and the analysis of color characteristics during different activity periods. The structure functions on a time scale from 1 to 100–300 days in the X-ray and optical spectral ranges have the form of the power law (SF ~ τ b ). However, their indices differ significantly. Color-index measurements using various apertures demonstrate that the color becomes bluer towards the galaxy nucleus. We may conclude that the relative amplitudes of short flares in the X-ray band are higher than those in the optical one and, conversely, the relative amplitudes of long flares in the X-ray band are slightly lower than those in the optical one, i.e., short events dominate in the X-ray band. A more detailed analysis of the correlation between the X-ray and optical emissions has revealed a fairly complex picture: different degrees of correlation between the optical and X-ray fluxes are observed at different times. As follows from the analysis of the surface photometry using both Maidanak data and HST data, an intensity asymmetry at the SG central region image is observed at different periods. The existence of a second component might be supposed. The radius of the active region itself inside the SG kernel is 40-50 parsec.