Active Galactic Nuclei (AGN) emit a substantial fraction of their total radiated power in the EUV passband, because spectroscopically this band is situated at or near the peak of the 'big blue bump,' which is bounded on either side by the UV and soft X-ray excesses. Owing to the lack of observational data, the shape of AGN spectra in the EUV is not well known. This paper presents broad band (65-190 eV) count rates of 11 AGN detected by the Extreme Ultraviolet Explorer (EUVE). Assuming a power law spectral shape for the EUV and soft X-ray energies, we demonstrate that the photon indices of the sources are considerably steeper than typical AGN indices. For 6 sources where ROSAT data are available to provide a more precise determination of their spectral parameters in the 0.1-2.5 keV range, we have used these parameters to compute predicted EUVE count rates and compared them with the observed values. The two sets of quantities agree to within experimental error. We conclude that there is no evidence of spectral steepening or turn-over of the soft X-ray excess at EUV wavelengths for a sample of AGN which covers a wide range of brightness.


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    Titel :

    EUV emission from a sample of Active Galactic Nuclei


    Beteiligte:
    Lieu, R. (Autor:in) / Mittaz, J. (Autor:in) / Bowyer, S. (Autor:in) / Lewis, J. (Autor:in) / Hwang, C.-Y. (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    1995-01-01



    Medientyp :

    Sonstige


    Format :

    Keine Angabe


    Sprache :

    Englisch


    Schlagwörter :


    EUV Emission from a Sample of Active Galactic Nuclei

    Lieu, R. / Mittaz, J. / Bowyer, S. et al. | British Library Conference Proceedings | 1995



    Active galactic nuclei: the view from space

    Perola, G. C. | British Library Online Contents | 1992


    Multiwavelength Monitoring of Active Galactic Nuclei

    Urry, C. M. / COSPAR | British Library Conference Proceedings | 1993


    ROSAT: Observations of active galactic nuclei

    Fink, H. | British Library Online Contents | 1992