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.
|出版ステータス||Published - 2003 1 1|
ASJC Scopus subject areas
- Space and Planetary Science
- Astronomy and Astrophysics