Comparison between Optically Selected and X-Ray Selected Active Galactic Nuclei

  • A. Franceschini
  • I. M. Gioia
  • T. Maccacaro
Part of the Astrophysics and Space Science Library book series (ASSL, volume 121)


We compare statistical properties on optically selected and X-ray selected Active Galactic Nuclei by using the available data on the corresponding distributions of the X-ray to optical luminosity ratio. We show that these computations critically depend on the width of these distributions. The use of the observed ones leads to significant inconsistencies between predictions and observations. However, if we assume that these distributions have boon “broadened” by external effects, and consequently we use narrower intrinsic widths, we can eliminate most of the discrepancies.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Avni,Y. and Tananhaum,H., 1982, Ap.J.(Letters) 262, L17.ADSCrossRefGoogle Scholar
  2. Cheng,F.Z., Danese,L., De Sotti,G. and Franceschini,A., 1985, MNRAS 212, 857.ADSGoogle Scholar
  3. Danese,L., De Zotti,G. and Franceschini,A., 1985, Astr. Ap. 143, 277.ADSGoogle Scholar
  4. Franceschini,A., Gioia,I.M. and Maccacaro,T., 1985, submitted to Ap.J.Google Scholar
  5. Kriss,G.A. and Canizares,R.G., 1985, submitted to Ap.J.Google Scholar
  6. Maccacaro,T., 1984, in “X-ray and UV emission from Active Galactic Nuclei”, eds. W. Brinkman and J. Trumper, pag. 63.Google Scholar
  7. Maccacaro,T. and Gioia,I.M., 1983, IAU Symp. 104, eds. G.O. Abell. and G. Chincarini, pag. 7.Google Scholar
  8. Maccacaro,T., Gioia,I.M. and Stocke,J.T., 1984, Ap.J. 283, 486.ADSCrossRefGoogle Scholar
  9. Schmidt,M. and Green,R., 1983, Ap.J. 269, 352.ADSCrossRefGoogle Scholar
  10. Setti,G., 1984, in “X-ray and UV emission from Active Galactic Nuclei”, eds. W. Brinkman and J. Trumper, pag. 243.Google Scholar
  11. Zamorani,G., 1984a, in “X-ray Astronomy 84”, eds. M. oda and S. Giacconi, pag. 419.Google Scholar
  12. Zamorani,G., 1984b, in “VLBI and Compact Radio Sources”, eds. R. Fanti, K. Kellermann and G. Setti, pag. 85.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1986

Authors and Affiliations

  • A. Franceschini
    • 1
  • I. M. Gioia
    • 2
    • 3
  • T. Maccacaro
    • 2
    • 3
  1. 1.Vicolo OsservatorioIstituto di AstronomiaPadovaItaly
  2. 2.Center for AstrophysicsCambridgeUSA
  3. 3.Istituto di RadioastronomiaCNRBolognaItaly

Personalised recommendations