Detailed Shape and Evolutionary Behavior of the X-Ray Luminosity Function of Active Galactic Nuclei

Journal
Date Issued
2015
Author(s)
Miyaji, T.
•
Hasinger, G.
•
Salvato, M.
•
Brusa, M.
•
Cappelluti, N.
•
Civano, F.
•
Puccetti, S.
•
Elvis, M.
•
Brunner, H.
•
Fotopoulou, S.
•
Ueda, Y.
•
Griffiths, R. E.
•
Koekemoer, A. M.
•
Akiyama, M.
•
•
•
•
Merloni, A.
•
Vignali, C.
DOI
Description
This work is supported by UNAM-DGAPA Grant PAPIIT IN104113 and CONACyT Grant Científica Básica 179662 (to T.M.). Also acknowledged are the FP7 Career Integration Grant “eEASy” CIG 321913 (to M.B.), financial support from INAF under Contracts PRIN-INAF-2011 and PRIN-INAF-2012 (to N.C., A.C., and R.G.), and the Grant-in-Aid for Scientific Research 26400228 (to Y.U.) from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT). We gratefully acknowledge the contributions of the entire COSMOS collaboration, consisting of more than 100 scientists. More information about the COSMOS survey is available at http://www.astro.caltech.edu/cosmos . The authors thank Len Cowie and his collaborators for allowing us to use their unpublished spectroscopic redshifts and Murray Brightman for his advice on CTK AGNs. Facilities: XMM , CXO , ASCA , Swift
Abstract
We construct the rest-frame 2-10 keV intrinsic X-ray luminosity function (XLF) of active galactic nuclei (AGNs) from a combination of X-ray surveys from the all-sky Swift BAT survey to the Chandra Deep Field South. We use ̃3200 AGNs in our analysis, which covers six orders of magnitude in flux. The inclusion of XMM and Chandra COSMOS data has allowed us to investigate the detailed behavior of the XLF and evolution. In deriving our XLF, we take into account realistic AGN spectrum templates, absorption corrections, and probability density distributions in photometric redshift. We present an analytical expression for the overall behavior of the XLF in terms of the luminosity-dependent density evolution, smoothed two-power-law expressions in 11 redshift shells, three-segment power-law expression of the number density evolution in four luminosity classes, and binned XLF. We observe a sudden flattening of the low luminosity end slope of the XLF slope at z ≳0.6. Detailed structures of the AGN downsizing have also been revealed, where the number density curves have two clear breaks at all luminosity classes above log {{L}X}\gt 43. The two-break structure is suggestive of two-phase AGN evolution, consisting of major merger triggering and secular processes.
Volume
804
Issue
2
Start page
104
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2015ApJ...804..104M
Rights
open.access
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