(ACCEPTED BY THE ASTROPHYSICAL JOURNAL LETTERS) Preprint typeset using LATEX style emulateapj v. 11/10/09 KEPLER OBSERVATIONS OF RAPID OPTICAL VARIABILITY IN ACTIVE GALACTIC NUCLEI

Over three quarters in 2010–2011, Kepler monitored optical emission from four active galactic nuclei (AGN) with ∼30 min sampling,> 90 % duty cycle and. 0.1 % repeatability. These data determined the AGN optical fluctuation power spectral density functions (PSDs) over a wide range in temporal frequency. Fits to these PSDs yielded power law slopes of −2.6 to −3.3, much steeper than typically seen in the X-rays. We find evidence that individual AGN exhibit intrinsically different PSD slopes. The steep PSD fits are a challenge to recent AGN variability models but seem consistent with first order MRI theoretical calculations of accretion disk fluctuations