Twelve years of X-ray and optical variability in the Seyfert galaxy NGC 4051
Journal: Monthly Notices of the Royal Astronomical Society
Year: 2010

We discuss the origin of the optical variations in the narrow-line Seyfert 1 galaxy NGC 4051 and present the results of a cross-correlation study using X-ray and optical light curves spanning more than 12 years. The emission is highly variable in all wavebands, and the amplitude of the optical variations is found to be smaller than that of the X-rays, even after correcting for the contaminating host galaxy flux falling inside the photometric aperture. The optical power spectrum is best described