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The 2-10 keV unabsorbed luminosity function of AGN from the LSS, CDFS, and COSMOS surveys

Ranalli, P. LU ; Koulouridis, E.; Georgantopoulos, I.; Fotopoulou, S.; Hsu, L. T.; Salvato, Mara; Comastri, A.; Pierre, M.; Cappelluti, N. and Carrera, F. J., et al. (2016) In Astronomy and Astrophysics 590.
Abstract

The XMM-Large scale structure (XMM-LSS), XMM-Cosmological evolution survey (XMM-COSMOS), and XMM-Chandra deep field south (XMM-CDFS) surveys are complementary in terms of sky coverage and depth. Together, they form a clean sample with the least possible variance in instrument effective areas and point spread function. Therefore this is one of the best samples available to determine the 2-10 keV luminosity function of active galactic nuclei (AGN) and their evolution. The samples and the relevant corrections for incompleteness are described. A total of 2887 AGN is used to build the LF in the luminosity interval 1042-1046 erg s-1 and in the redshift interval 0.001-4. A new method to correct for absorption... (More)

The XMM-Large scale structure (XMM-LSS), XMM-Cosmological evolution survey (XMM-COSMOS), and XMM-Chandra deep field south (XMM-CDFS) surveys are complementary in terms of sky coverage and depth. Together, they form a clean sample with the least possible variance in instrument effective areas and point spread function. Therefore this is one of the best samples available to determine the 2-10 keV luminosity function of active galactic nuclei (AGN) and their evolution. The samples and the relevant corrections for incompleteness are described. A total of 2887 AGN is used to build the LF in the luminosity interval 1042-1046 erg s-1 and in the redshift interval 0.001-4. A new method to correct for absorption by considering the probability distribution for the column density conditioned on the hardness ratio is presented. The binned luminosity function and its evolution is determined with a variant of the Page-Carrera method, which is improved to include corrections for absorption and to account for the full probability distribution of photometric redshifts. Parametric models, namely a double power law with luminosity and density evolution (LADE) or luminosity-dependent density evolution (LDDE), are explored using Bayesian inference. We introduce the Watanabe-Akaike information criterion (WAIC) to compare the models and estimate their predictive power. Our data are best described by the LADE model, as hinted by the WAIC indicator. We also explore the recently proposed 15-parameter extended LDDE model and find that this extension is not supported by our data. The strength of our method is that it provides unabsorbed, non-parametric estimates, credible intervals for luminosity function parameters, and a model choice based on predictive power for future data.

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published
subject
keywords
Galaxies: active, Methods: statistical, Surveys, X-rays: general
in
Astronomy and Astrophysics
volume
590
publisher
EDP Sciences
external identifiers
  • scopus:84969836648
  • wos:000378106800022
ISSN
0004-6361
DOI
10.1051/0004-6361/201527013
language
English
LU publication?
yes
id
a3c38b22-9021-47bf-b328-4d2358d4f2e6
date added to LUP
2017-02-08 09:22:34
date last changed
2017-09-24 05:06:55
@article{a3c38b22-9021-47bf-b328-4d2358d4f2e6,
  abstract     = {<p>The XMM-Large scale structure (XMM-LSS), XMM-Cosmological evolution survey (XMM-COSMOS), and XMM-Chandra deep field south (XMM-CDFS) surveys are complementary in terms of sky coverage and depth. Together, they form a clean sample with the least possible variance in instrument effective areas and point spread function. Therefore this is one of the best samples available to determine the 2-10 keV luminosity function of active galactic nuclei (AGN) and their evolution. The samples and the relevant corrections for incompleteness are described. A total of 2887 AGN is used to build the LF in the luminosity interval 10<sup>42</sup>-10<sup>46</sup> erg s<sup>-1</sup> and in the redshift interval 0.001-4. A new method to correct for absorption by considering the probability distribution for the column density conditioned on the hardness ratio is presented. The binned luminosity function and its evolution is determined with a variant of the Page-Carrera method, which is improved to include corrections for absorption and to account for the full probability distribution of photometric redshifts. Parametric models, namely a double power law with luminosity and density evolution (LADE) or luminosity-dependent density evolution (LDDE), are explored using Bayesian inference. We introduce the Watanabe-Akaike information criterion (WAIC) to compare the models and estimate their predictive power. Our data are best described by the LADE model, as hinted by the WAIC indicator. We also explore the recently proposed 15-parameter extended LDDE model and find that this extension is not supported by our data. The strength of our method is that it provides unabsorbed, non-parametric estimates, credible intervals for luminosity function parameters, and a model choice based on predictive power for future data.</p>},
  articleno    = {A80},
  author       = {Ranalli, P. and Koulouridis, E. and Georgantopoulos, I. and Fotopoulou, S. and Hsu, L. T. and Salvato, Mara and Comastri, A. and Pierre, M. and Cappelluti, N. and Carrera, F. J. and Chiappetti, L. and Lassas-Clerc, Narjisse and Gilli, R. and Iwasawa, K. and Pacaud, F. and Paltani, S. and Plionis, E. and Centis Vignali, M},
  issn         = {0004-6361},
  keyword      = {Galaxies: active,Methods: statistical,Surveys,X-rays: general},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {The 2-10 keV unabsorbed luminosity function of AGN from the LSS, CDFS, and COSMOS surveys},
  url          = {http://dx.doi.org/10.1051/0004-6361/201527013},
  volume       = {590},
  year         = {2016},
}