Abstract The results of the initial stage of the CfA survey of Quasar Energy Distributions (QEDs) are reviewed. Einstein Imaging Proportional Counter (IPC) spectra of 33 quasars have been studied by fitting a single power law slope and absorption by an equivalent column density of neutral hydrodgen, N H. A wide range of energy index, α E, is seen and α E increases as the radio loudness of a quasar decreases. Comparison with the higher energy HEAO-A2 data leads us to a two-component model for th x-ray spectrum. The x-ray column density is systematically lower than the 21 cm measured Galactic column density along the same line of sight. This discrepancy is not present in a comparison sample of Bl Lac objects and so the cause must be intrinsic to the quasar. A third component, an ultra-soft excess (<0.28keV) above a single power law in the quasar spectra, provides a plausible explanation. This excess could be the high energy tail of the blue bump in the optical and ultra-violet (UV).


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    Titel :

    Einstein spectra of quasars


    Beteiligte:

    Erschienen in:

    Erscheinungsdatum :

    1988-01-01


    Format / Umfang :

    9 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch



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