Article (Scientific journals)
Spectral Energy Distributions of Hard X-Ray Selected Active Galactic Nuclei in the XMM-Newton Medium Deep Survey
Polletta, M.; Tajer, M.; Maraschi, L. et al.
2007In Astrophysical Journal, 663, p. 81-102
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The authors thank http://arxiv.org/abs/astro-ph/0703255 for their preprint deposit authorization. The original publication can be found in the Astrophysical Journal.


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Keywords :
Infrared: Galaxies; Galaxies: Quasars: General; X-Rays: Galaxies; Galaxies: Active
Abstract :
[en] We present the SEDs of a hard X-ray selected sample containing 136 sources with F[SUB]2-10keV[/SUB]>10[SUP]-14[/SUP] erg cm[SUP]-2[/SUP] s[SUP]-1[/SUP] 132 are AGNs. The sources are detected in a 1 deg[SUP]2[/SUP] area of the XMM-Newton Medium Deep Survey where optical data from the VVDS and CFHTLS and infrared data from the SWIRE survey are available. Based on a SED fitting technique we derive photometric redshifts with sigma(1+z)=0.11 and 6% of outliers and identify AGN signatures in 83% of the objects. This fraction is higher than derived when a spectroscopic classification is available. The remaining 17[SUP]+9[/SUP][SUB]-6[/SUB]% of AGNs show star-forming galaxy SEDs (SF class). The sources with AGN signatures are divided in two classes, AGN1 (33[SUP]+6[/SUP][SUB]-1[/SUB]%) and AGN2 (50[SUP]+6[/SUP][SUB]-11[/SUB]%). The AGN1 and AGN2 classes include sources whose SEDs are fitted by type 1 and type 2 AGN templates, respectively. On average, AGN1s show soft X-ray spectra, consistent with being unabsorbed, while AGN2s and SFs show hard X-ray spectra, consistent with being absorbed. The analysis of the average SEDs as a function of X-ray luminosity shows a reddening of the infrared SEDs, consistent with a decreasing contribution from the host galaxy at higher luminosities. The AGNs in the SF classes are likely obscured in the mid-infrared, as suggested by their low L[SUB]3-20mum[/SUB]/L[SUP]corr[/SUP][SUB]0.5-10keV[/SUB] ratios. We confirm the previously found correlation for AGNs between the radio luminosity and the X-ray and the mid-infrared luminosities. The X-ray-radio correlation can be used to identify heavily absorbed AGNs. However, the estimated radio fluxes for the missing AGN population responsible for the bulk of the background at E>10 keV are too faint to be detected even in the deepest current radio surveys.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Polletta, M.;  Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093-0424.
Tajer, M.;  INAF-Osservatorio di Brera, via Brera 28, 20121 Milano, Italy. ; Università degli studi di Milano-Bicocca, Dipartimento di fisica, Piazza della Scienza 3, 20126 Milano, Italy.
Maraschi, L.;  INAF-Osservatorio di Brera, via Brera 28, 20121 Milano, Italy.
Trinchieri, G.;  INAF-Osservatorio di Brera, via Brera 28, 20121 Milano, Italy.
Lonsdale, C. J.;  Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093-0424.
Chiappetti, L.;  INAF-IASF Milano, via Bassini 15, I-20133 Milano, Italy.
Andreon, S.;  INAF-Osservatorio di Brera, via Brera 28, 20121 Milano, Italy.
Pierre, M.;  CEA Saclay, DSM/DAPNIA, Service d'Astrophysique, 91191 Gif-sur-Yvette, France.
Le Fèvre, O.;  Laboratoire d'Astrophysique de Marseille, UMR 6110 CNRS-Université de Provence, Traverse du Siphon, BP 8, 13012 Marseille, France.
Zamorani, G.;  INAF-Osservatorio di Bologna, via Ranzani 1, 40127 Bologna, Italy.
Maccagni, D.;  INAF-IASF Milano, via Bassini 15, I-20133 Milano, Italy.
Garcet, Olivier ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Surdej, Jean  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Franceschini, A.;  Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, I-35122, Padova, Italy.
Alloin, D.;  CEA Saclay, DSM/DAPNIA, Service d'Astrophysique, 91191 Gif-sur-Yvette, France.
Shupe, D. L.;  Spitzer Science Center, California Institute of Technology, 100-22, Pasadena, CA 91125.
Surace, J. A.;  Spitzer Science Center, California Institute of Technology, 100-22, Pasadena, CA 91125.
Fang, F.;  Spitzer Science Center, California Institute of Technology, 100-22, Pasadena, CA 91125.
Rowan-Robinson, M.;  Astrophysics Group, Blackett Laboratory, Imperial College, Prince Consort Road, London, SW7 2BW, UK.
Smith, H. E.;  Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093-0424.
Tresse, L.;  Laboratoire d'Astrophysique de Marseille, UMR 6110 CNRS-Université de Provence, Traverse du Siphon, BP 8, 13012 Marseille, France.
More authors (11 more) Less
Language :
English
Title :
Spectral Energy Distributions of Hard X-Ray Selected Active Galactic Nuclei in the XMM-Newton Medium Deep Survey
Publication date :
2007
Journal title :
Astrophysical Journal
ISSN :
0004-637X
eISSN :
1538-4357
Publisher :
University of Chicago Press, Chicago, United States - Illinois
Volume :
663
Pages :
81-102
Peer reviewed :
Peer Reviewed verified by ORBi
Commentary :
http://arxiv.org/abs/astro-ph/0703255
Available on ORBi :
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