Optical variability structure function of low-luminosity AGNs using ATLAS light curves

Abstract

The origin of the optical flux variability in active galactic nuclei (AGNs) is largely unknown. Previous studies have correlated features of the variability structure function (SF) with AGN properties, though they mostly involved high-luminosity AGNs to avoid biases from host galaxy flux. In this work, we characterize optical variability in a sample of 246 low-luminosity AGNs at (Formula presented) from the Six-degree Field Galaxy Survey through the ensemble variability SF. We use light curves from the Asteroid Terrestrial-impact Last Alert System with a cadence of (Formula presented) 2 d over 8 yr, and perform host–AGN decomposition on recent spectra to obtain the host fraction. We find tha..