NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-25 T16:34:06 PDT
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For refcode 1993A&A...274..105W:
Retrieve 58 NED objects in this reference.
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NED Abstract

Copyright by European Southern Observatory (ESO). Reproduced by permission
1993A&A...274..105W The ultraviolet to soft X- ray bump of Seyfert 1 type active galactic nuclei R. Walter and N.H. Fink Max Planck Institut fur Extratertestrische Physik, Giessenbachstrasse, W- 8046 Garching b. Munchen, Germany Received November 5, 1992; accepted February 22, 1993 Abstract. The soft X-ray (0.1 - 2.4 keV) emission of 58 Seyfert type active galactic nuclei have been studied using the spectra obtained during the ROSAT all sky survey. These spectra are well represented by power law models with photon indices ranging between 1.6 and 3.4. The spectra usually do not show intrinsic absorption. A notable exception is Mrk 766 which is probably absorbed by molecular clouds located in the inner part of the Narrow Line Region. A soft X-ray excess above the extrapolation of the hard X-ray spectrum is detected in 90% of the sources. These soft X-ray excesses are well correlated to the strength of the "big blue bump" observed with IUE except for those sources which are highly absorbed in the ultraviolet. The strength of the ultraviolet to soft X-ray bump varies by a factor of hundred from object to object and it is not correlated either to the luminosity or to the radio-loudness. The data are consistent with the assumption that the ultraviolet to soft X-ray bump is similarly shaped in all Seyfert 1 galaxies of our sample. Neither thin nor thick accretion disk models can reproduce the available observations in a natural way. Key words: galaxies: Seyfert - ultraviolet: galaxies - X-rays: galaxies
Retrieve 58 NED objects in this reference.
Please click here for ADS abstract

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