Population properties of AGN in the soft X-ray band

Research output: Contribution to journalArticle (Academic Journal)


Maximum likehood analysis can be used to separate the intrinsic dispersion of spectral index from the measuring errors for X-ray observed samples of active galactic nuclei (AGN). A finite sigma tends to introduce selection biases, compels the use of large samples in searches for intrinsic properties, and can mask quite substantial trends in X-ray spectral index with other source properties. The property which appears to affect the mean spectral index is the relative strength of radio emission. The connection between radio and X-ray luminosity is discussed. Observed trends to flatter AGN X-ray spectral components with higher energy may be important in evaluating the composite spectrum of AGN contributing to the cosmic X-ray background.
Original languageEnglish
Pages (from-to)719-726
JournalIn ESA, The 23rd ESLAB Symposium on Two Topics in X Ray Astronomy. Volume 2: AGN and the X Ray Background p 719-726 (SEE N90-25841 19-89)
Publication statusPublished - 1 Nov 1989


  • Active Galactic Nuclei
  • Star Distribution
  • X Ray Sources
  • X Ray Spectra
  • Background Radiation
  • Bl Lacertae Objects
  • Cosmic Rays
  • Galactic Radiation
  • Luminosity
  • Maximum Likelihood Estimates
  • Quasars
  • Spectral Signatures


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