Optical and X-ray variability of Seyfert galaxies NGC 5548, NGC 7469, NGC 3227, NGC 4051, NGC 4151, Mrk 509, Mrk 79, and Akn 564 and quasar 1E 0754
We present our results of cross-correlation analysis of optical and X-ray light curves for eight Seyfert galaxies NGC 5548, NGC 7469, NGC 3227, NGC 4051, NGC 4151, Mrk 509, Mrk 79, and Akn 564 and for the optical spectrum of quasar 1E 0754. we obtained a high maximum correlation coefficient between variations in the optical and X-ray spectral regions for the Seyfert galaxy NGC 5548 and NGC 7469 (0.73 and 0.79, respectively). The time of lag calculated at the maximum of cross-correlation function is 2.800 +3.12 -1.58 for NGC 5548 and 0.6 +0.9 - 1.3 days for NGC 7469. The result is an evidence in favour of the assumption of Compton scattering of the X-ray flux variation in the optical region for these galaxies. The wing (except for the main maximum correspondingly to the delay in optical region in relation to X-ray region) exists in the part of the cross-correlation functions, which corresponds to the delay in the X-ray region in relation to optical one for the whole sample (except for Akn 564 and NGC 4151) with the time of lag of about 10 days.