Optical variability of the blazar 3C 454.3 during 2007-2010

The optical variability of the blazar 3C 454.3 during 2007-2010 has been studied using the results of multicolor ( BVRIJHK ) observations. The existence of two variable synchrotron sources was found. The first is responsible for the flux variability of small amplitude, the second – for the flares. In each flare the relative SED of variable source was found to be constant but spectral indexes were different in different flares. This fact points to impossibility to explain the global variability only by geometrical reasons. The observed color variability is due to a superposition of the variable and constant components with different SEDs.