A link between X-ray variability and ultraviolet emission in Seyfert 1 type AGN.
Abstract
We analyse the behaviour of X-ray spectral variations in Seyfert 1 type active galactic nuclei observed many times in the 2-10 keV energy band. The selected sources are compatible with a separation into two groups distinguished by different kinds of X-ray variability and by different ratios of ultraviolet to X-ray fluxes. In the first group of objects the X-ray spectral variations are related to the ratio of the medium X-ray flux to the ultraviolet or soft X-ray flux while in the second group the spectra steepen when the sources brighten. The two different kinds of X-ray variability are related to the strength of the blue bump and may be linked to the relative importance of different cooling processes in the X-ray sources of these objects.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 1992
- Bibcode:
- 1992A&A...266...65W
- Keywords:
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- Active Galactic Nuclei;
- Seyfert Galaxies;
- Ultraviolet Emission;
- X Ray Sources;
- Astronomical Spectroscopy;
- Energy Bands;
- Exosat Satellite;
- Spaceborne Astronomy;
- Astrophysics