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.
