Active galactic nuclei (AGNs) exhibit complex variability across multiple wavelengths, reflecting diverse physical processes near their central engines. This work investigates the temporal variability of four AGNs Mrk~509, NGC~5548, NGC~4151, and NGC~4593 using multifractal detrended moving average (MFDMA) analysis and Fisher-Shannon information plane applied to their X-ray, ultraviolet, and optical light curves. These methods quantify the scaling behavior and complexity of the variability, revealing persistent correlations and distinct variability patterns across energy bands. The Fisher-Shannon analysis further characterizes the degree of stochasticity and structural complexity in the emission processes. Our findings support the interpretation that multifractal and information-theoretic measures provide effective diagnostics of the physical mechanisms driving AGN variability. This study demonstrates the utility of advanced time series techniques as effective diagnostics of AGN variability mechanisms.
@article{arxiv.2605.08998,
title = {Complexity and Multifractal Variability in Multi-Band Emission of Seyfert AGN},
author = {R. A. A. Souza and E. Hatziminaoglou and A. de Pádua Santos and T. Stosic},
journal= {arXiv preprint arXiv:2605.08998},
year = {2026}
}