DETAILED SHAPE AND EVOLUTIONARY BEHAVIOR OF THE X-RAY LUMINOSITY FUNCTION OF ACTIVE GALACTIC NUCLEI

Abstract

We construct the rest-frame 2--10 keV intrinsic X-ray luminosity function of\nActive Galactic Nuclei (AGNs) from a combination of X-ray surveys from the\nall-sky Swift BAT survey to the Chandra Deep Field-South. We use ~3200 AGNs in\nour analysis, which covers six orders of magnitude in flux. The inclusion of\nthe XMM and Chandra COSMOS data has allowed us to investigate the detailed\nbehavior of the XLF and evolution. In deriving our XLF, we take into account\nrealistic AGN spectrum templates, absorption corrections, and probability\ndensity distributions in photometric redshift. We present an analytical\nexpression for the overall behavior of the XLF in terms of the\nluminosity-dependent density evolution, smoothed two power-law expressions in\n11 redshift shells, three-segment power-law expression of the number density\nevolution in four luminosity classes, and binned XLF. We observe a sudden\nflattening of the low luminosity end slope of the XLF slope at z>~0.6. Detailed\nstructures of the AGN downsizing have been also revealed, where the number\ndensity curves have two clear breaks at all luminosity classes above log LX>43.\nThe two break structure is suggestive of two-phase AGN evolution, consisting of\nmajor merger triggering and secular processes.\n