X-Ray Active Galactic Nuclei / AGN Variability with Hour to Month Timescales
Abstract
Periodic flares and dips in the Active Galactic Nuclei (AGN) X-ray light curves are explained by bright spots on an accretion disk surface. For a disk seen almost edge-on the spots are eclipsed or Doppler beamed and this occasionally produces short sequences of repeated dips or flares. Spots located in a narrow range of radii, produce distinct peaks in the variability power spectra. When the range is broad, a power spectrum is produced with beta = 7/3 for spots with long lifetimes on a Keplerian disk. Short lifetimes and non-Keplerian rotation are consistent with beta between 1 and 2.
- Publication:
-
Two Topics in X-Ray Astronomy, Volume 1: X Ray Binaries. Volume 2: AGN and the X Ray Background
- Pub Date:
- November 1989
- Bibcode:
- 1989ESASP.296..871A
- Keywords:
-
- Accretion Disks;
- Active Galactic Nuclei;
- Black Holes (Astronomy);
- Power Spectra;
- Variability;
- Astronomical Models;
- Background Radiation;
- Light Curve;
- Stellar Flares;
- Time Dependence;
- X Ray Spectra;
- Astronomy