EXOSAT observations of a strong soft X-ray excess in MKN 841.
Culhane, J. L.; Fabian, A. C.; Branduardi-Raymont, G.; Ward, M. J.; Tennant, A. F.; Hazard, C.; Arnaud, K. A.; Shafer, R. A.; McGlynn, T. A.
United Kingdom, United States
Abstract
EXOSAT observations of the spectrum of the Seyfert 1 galaxy MKN 841 show that it is well-fitted by a power law of photon index 1.6, similar to that of other Seyferts, and a large additional soft component. The X-ray luminosity over the observed band exceeds 4×1044erg s-1. A single-temperature blackbody fit to the soft X-rays and the short-wavelength ultraviolet continuum gives a luminosity of 2×1046erg s-1 while an accretion disc spectrum fitted to the same points gives a luminosity of 4.3×1045erg s-1. The flux measured by both the EXOSAT low- and medium-energy instruments exhibits 12 per cent amplitude variability on a time-scale of one day.