Nonlinear variability of NGC 4151.

Abstract

We have collected all literature photometric data obtained in the B band for the Seyfert galaxy NGC4151 over the period 1910-1991, reduced them to the standard B_T_ photometric system and derived nuclear magnitudes by subtracting the light contribution from the underlying extended bulge component. The spectral analysis of the light curve shows no evidence for periodicities. The multifractal analysis clearly indicates a non linear intermittent behaviour, suggesting that the physical mechanism responsible for the variability of NGC 4151 may be similar to those which are at work in the OVV 3C 345.