Kepler Observations of Rapid Optical Variability in Active Galactic Nuclei
Abstract
Over three quarters in 2010-2011, Kepler monitored optical emission from four active galactic nuclei (AGNs) with ~30 minute sampling, >90% duty cycle, and lsim0.1% repeatability. These data determined the AGN optical fluctuation power spectral density (PSD) functions 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 AGNs exhibit intrinsically different PSD slopes. The steep PSD fits are a challenge to recent AGN variability models but seem consistent with first-order magnetorotational instability theoretical calculations of accretion disk fluctuations.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2011
- DOI:
- 10.1088/2041-8205/743/1/L12
- arXiv:
- arXiv:1111.0672
- Bibcode:
- 2011ApJ...743L..12M
- Keywords:
-
- accretion;
- accretion disks;
- black hole physics;
- galaxies: active;
- galaxies: Seyfert;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted by Astrophysical Journal Letters, 31 Oct 2011