NSA low-mass galaxies with long-term PTF obs.

We use difference imaging of Palomar Transient Factory (PTF) R-band observations to construct light curves with typical baselines of several years. We then search for subtle variations in the nuclear light output.

We determine whether detected variability is AGN-like by assessing the fit quality to a damped random walk model. We identify 417 variability-selected AGNs, including 237 with stellar masses between 10^7^ and 10^10^M_{sun}_. 75% of low-mass galaxies with AGN-like variability have narrow emission lines dominated by star formation. After controlling for nucleus magnitude, the fraction of variable AGNs is constant down to M_*_=10^9^M_{sun}_, suggesting no drastic decline in the BH occupation fraction down to this stellar mass regime.