Simultaneous multifrequency observations of the Seyfert 1 galaxy NGC 4051 : constant optical-infrared emission observed during large-amplitude X-ray variability.
Abstract
We report simultaneous infrared, optical, ultraviolet and X-ray observations of the low-luminosity Seyfert 1 galaxy, NGC 4051. A new method of reduction was developed to correct the optical flux for atmospheric variations due to seeing and extinction. The X-ray flux varied by factors of up to 2 on time-scales of tens of minutes whilst the optical flux remained steady to within 1 per cent. Our results rule out all models, including Compton scattering and synchrotron models, in which a single electron population is responsible for the formation of both the infrared- to-optical and the X-ray spectra. The optical emission region must be an order of magnitude larger than, or completely separate from, the X-ray source.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 1990
- Bibcode:
- 1990MNRAS.243..713D
- Keywords:
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- Active Galactic Nuclei;
- Infrared Astronomy;
- Light Emission;
- Seyfert Galaxies;
- X Ray Astronomy;
- Compton Effect;
- Luminosity;
- Stellar Spectra;
- Ultraviolet Astronomy;
- Astrophysics