TY - JOUR
T1 - Cosmological evolution of the hard X-ray AGN luminosity function
T2 - Formation history of supermassive black holes
AU - Ueda, Yoshihiro
AU - Akiyama, Masayuki
AU - Ohta, Kouji
AU - Miyaji, Takamitsu
PY - 2004
Y1 - 2004
N2 - The cosmological evolution of the hard X-ray luminosity function (HXLF) of Active Galactic Nuclei (AGN) is investigated in the 2-10 keV luminosity range of 1041.5 - 1046.5 erg s-1 as a function of redshift up to 3. From a combination of surveys conducted at photon energies above 2 keV with HEAO1, ASCA and Chandra, we construct a highly complete (>96%) sample consisting of 247 AGNs over the wide flux range of 10 -10 - 3.8 × 10-15 erg cm-2 s -1 (2-10 keV). We find that (i) the fraction of X-ray absorbed AGNs decreases with the intrinsic luminosity and (ii) the evolution of the HXLF of the whole AGNs (including both type-I and type-II AGNs) is best described with a luminosity dependent density evolution where the cutoff redshift increases with the luminosity. Our results directly constrain the evolution of AGNs that produce a major part of the hard X-ray background, thus solving its origin quantitatively. Based on these results, we discuss the formation history of supermassive black holes in galactic centers. The total accreted mass traced by the HXLF with an accretion mass-to-energy conversion factor of 0.1 is consistent with an estimate of SMBH mass density from the demography of galaxies in nearby universe.
AB - The cosmological evolution of the hard X-ray luminosity function (HXLF) of Active Galactic Nuclei (AGN) is investigated in the 2-10 keV luminosity range of 1041.5 - 1046.5 erg s-1 as a function of redshift up to 3. From a combination of surveys conducted at photon energies above 2 keV with HEAO1, ASCA and Chandra, we construct a highly complete (>96%) sample consisting of 247 AGNs over the wide flux range of 10 -10 - 3.8 × 10-15 erg cm-2 s -1 (2-10 keV). We find that (i) the fraction of X-ray absorbed AGNs decreases with the intrinsic luminosity and (ii) the evolution of the HXLF of the whole AGNs (including both type-I and type-II AGNs) is best described with a luminosity dependent density evolution where the cutoff redshift increases with the luminosity. Our results directly constrain the evolution of AGNs that produce a major part of the hard X-ray background, thus solving its origin quantitatively. Based on these results, we discuss the formation history of supermassive black holes in galactic centers. The total accreted mass traced by the HXLF with an accretion mass-to-energy conversion factor of 0.1 is consistent with an estimate of SMBH mass density from the demography of galaxies in nearby universe.
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U2 - 10.1143/PTPS.155.209
DO - 10.1143/PTPS.155.209
M3 - Review article
AN - SCOPUS:11144238337
SN - 0375-9687
VL - 155
SP - 209
EP - 216
JO - Progress of Theoretical Physics Supplement
JF - Progress of Theoretical Physics Supplement
ER -