The hard X-ray luminosity function from ASCA surveys

Y. Ueda, Masayuki Akiyama, K. Ohta, T. Miyaji

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


We summarize the nature of hard X-ray populations at "bright" fluxes > 10-13 erg cm-2 s-1 (2-10 keV) from optical identification of ASCA surveys, and present results of the hard X-ray luminosity function (HXLF) of Active Galactic Nuclei (AGN). Combined with HEAO1 and Chandra surveys we construct a hard-band selected sample with extremely high degree of completeness (>95%), consisting of 228 AGNs over the flux range 10-11 ∼ 3 × 10-15 erg cm-2 s-1 (2-10 keV). We find evidence that the percentage of "type-II" AGNs decreases with the intrinsic luminosity. The intrinsic HXLF of the whole AGNs (including type-II AGNs) is well described with the pure luminosity evolution (PLE) model up to redshift of 3. Our results directly constrain the evolution of AGNs that produce a major part of the hard X-ray background.

Original languageEnglish
Pages (from-to)36-39
Number of pages4
JournalAstronomische Nachrichten
Issue number1-2
Publication statusPublished - 2003 Jan 1
Externally publishedYes


  • Galaxies: active
  • Galaxies: evolution
  • X-rays

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics


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