Abstract We present five EXOSAT observations of the Seyfert galaxy NGC6814. The source is found to be variable at both soft (LE) and medium (ME) X-ray energies. The most remarkable characteristics of this variability are the regular recurrence of flares at 12000s intervals during a 1-day long ME observation, a dip in the ME flux by a factor of 2 in ∼ 300 s, and variable low-energy absorption in the X-ray spectrum on a timescale of months. The EXOSAT observations support the conclusion reached by Tennant et al. (1981) /1/ on the basis of HEAO-A2 observations that the X-ray behaviour of NGC6814 is unsual among AGN. We consider possible scenarios in which such behaviour may originate, and briefly discuss the issue of a ‘characteristics’ timescale of the variability of AGN.
The flux variability of the Seyfert galaxy NGC6814 as observed with exosat
Advances in Space Research ; 8 , 2-3 ; 61-64
1988-01-01
4 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Time variability of stellar coronal sources observed by EXOSAT
Elsevier | 1989
|Elsevier | 1989
|European X-ray observatory satellite (Exosat)
NTRS | 1983
Tema Archiv | 1981
|Tema Archiv | 1978
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