Exploring the Origins of Optical Variability in Active Galactic Nuclei: Correlations with Black Hole Properties, X-Ray, and Radio Emission

Abstract We study the optical variability characteristics of active galactic nuclei (AGN) from the Swift Burst Alert Telescope AGN catalog using approximately 5 yr of optical light curves from the Zwicky Transient Facility survey. We investigate dependencies of long-term optical variability amplitudes and timescales on (i) supermassive black hole (SMBH) mass, luminosity, and Eddington ratio to explore accretion disk dynamics; (ii) X-ray properties, such as spectral photon indices and fluxes, to study high-energy emission mechanisms; and (iii) radio characteristics, such as integrated fluxes and radio-loudness, indicating jet activity. We confirm a positive correlation between the variability timescale and SMBH mass, consistent with accretion disk thermal timescale expectations. While the timescale also correlates with luminosity, this trend arises from the strong mass–luminosity coupling in our sample rather than representing a separate physical dependence. Conversely, no significant dependence is found between optical variability and X-ray properties, indicating that high-energy processes may not substantially influence long-term optical variability. Additionally, a weak anticorrelation between optical variability and radio parameters suggests that jet activity does not dominate the observed long-term AGN optical variability. These results are consistent with long-term optical variability in AGN being governed predominantly by thermal emission from the accretion disk. Further investigations with larger samples are essential to refine these correlations and develop robust physical models integrating black hole properties, accretion disk physics, and multiwavelength radiative transfer.