Ryan, J. L.Grindlay, JonathanSiemiginowska, AnetaSobolewska, Malgorzata2020-02-052019-10-24Ryan, J. L., A. Siemiginowska, M. A. Sobolewska, and J. Grindlay. 2019. Characteristic Variability Timescales in the Gamma-Ray Power Spectra of Blazars. The Astrophysical Journal 885, no. 1: 11.1538-4357http://nrs.harvard.edu/urn-3:HUL.InstRepos:42389097Characteristic variability timescales in blazar γ-ray light curves can provide insights into the physical processes responsible for γ-ray variability. The power spectral density (PSD) is capable of revealing such timescales, which may appear as breaks or periodicities. Continuous-time autoregressive moving-average (CARMA) models can be used to accurately estimate a light curve’s PSD. Through a light-curve simulation study, we develop a methodology to identify PSD breaks using CARMA models. Using this methodology, we study the γ-ray light curves of 13 bright blazars observed with the Fermi Large Area Telescope in the 0.1-300 GeV band over 9.5 yr. We present the blazar γ-ray PSDs, which provide evidence for low-frequency breaks on timescales ̃1 yr in four sources, and an additional high-frequency break on a timescale ̃9 days in one source.en-USSpace and Planetary ScienceAstronomy and AstrophysicsJournal Article2020-02-0510.3847/1538-4357/ab426a