Cosmological Evolution of the Hard X-ray AGN Luminosity Function and the Origin of the Hard X-ray Background

摘要: We investigate the cosmological evolution of hard X-ray luminosity function (HXLF) Active Galactic Nuclei (AGN) in 2-10 keV range 10^{41.5} - 10^{46.5} erg s^-1 as a redshift up to 3. From combination surveys conducted at photon energies above 2 with HEAO1, ASCA, and Chandra, we construct highly complete (>96%) sample consisting 247 AGNs over wide flux 10^{-10} 3.8*10^{-15} cm^-2 (2-10 keV). For our purpose, develop an extensive method calculating intrinsic (before-absorption) HXLF absorption (N_H) function. This utilizes maximum likelihood fully correcting for observational biases consideration spectrum each source. find that (i) fraction absorbed decreases (ii) all (including both type-I type-II AGNs) is best described dependent density (LDDE) where cutoff increases luminosity. Our results directly constrain produce major part background, thus solving its origin quantitatively. A NH enables us purely "observation based" population synthesis model. present basic consequences this model, discuss contribution Compton-thick rest background.