Long Timescale X-Ray Variability in Active Galactic Nuclei / AGN
Abstract
Long timescale medium energy light curves are constructed for a number of Active Galactic Nuclei (AGN), using data primarily from EXOSAT, Einstein, HEAO-1, and Ariel 5. Power spectra for these light curves were compared to the spectra of identically sampled simulated light curves with known spectral properties. It is concluded that reliable results can be obtained for some of the brighter AGN. Results for NGC 4151 are presented. This power spectrum is combined with a short timescale EXOSAT power spectrum to search for a characteristic timescale at low frequencies. It is found that the power spectrum of NGC 4151 is similar to 1/f noise on long timescales, but the sharp turnover seen in Cygnus X-1 is not observed.
- 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..865A
- Keywords:
-
- Active Galactic Nuclei;
- Light Curve;
- Power Spectra;
- Time Series Analysis;
- Variability;
- X Ray Spectra;
- Background Radiation;
- Computerized Simulation;
- Data Processing;
- Noise Spectra;
- Spectrum Analysis;
- Astronomy