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dc.contributor.authorGeorgantopoulos, Ioannis
dc.contributor.authorComastri, Andrea
dc.contributor.authorVignali, Cristian
dc.contributor.authorRanalli, Piero
dc.contributor.authorRovilos, Emmanouel
dc.contributor.authorIwasawa, Kazushi
dc.contributor.authorGilli, Roberto
dc.contributor.authorCappelluti, Nico
dc.contributor.authorCarrera Troyano, Francisco Jesús 
dc.contributor.authorFritz, Jacopo
dc.contributor.authorBrusa, Marcella
dc.contributor.authorElbaz, David
dc.contributor.authorMullaney, James R.
dc.contributor.authorCastelló Mor, Núria
dc.contributor.authorBarcons Jauregui, Francesc Xavier
dc.contributor.authorTozzi, Paolo
dc.contributor.authorBalestra, Italo
dc.contributor.authorFalocco, Serena
dc.contributor.otherUniversidad de Cantabriaes_ES
dc.date.accessioned2013-12-26T12:41:35Z
dc.date.available2013-12-26T12:41:35Z
dc.date.issued2013-07
dc.identifier.issn0004-6361
dc.identifier.issn1432-0746
dc.identifier.otherAYA2010-21490-C02-01
dc.identifier.urihttp://hdl.handle.net/10902/4093
dc.description.abstractThe Chandra Deep Field is the region of the sky with the highest concentration of X-ray data available: 4 Ms of Chandra and 3 Ms of XMM-Newton data, allowing excellent quality spectra to be extracted even for faint sources. We took advantage of this to compile a sample of heavily obscured active galactic nuclei (AGN) using X-ray spectroscopy. We selected our sample among the 176 brightest XMM-Newton sources, searching for either flat X-ray spectra (Γ < 1.4 at the 90% confidence level) suggestive of a reflection dominated continuum or an absorption turn-over suggestive of a column density higher than ≈ 1024 cm-2. We found a sample of nine heavily-obscured sources satisfying the above criteria. Four of these show statistically significant FeKα lines with large equivalent widths (three out of four have equivalent widths consistent with 1 keV) suggesting that these are the most certain Compton-thick AGN candidates. Two of these sources are transmission dominated while the other two are most probably reflection dominated Compton-thick AGN. Although this sample of four sources is by no means statistically complete, it represents the best example of Compton-thick sources found at moderate-to-high redshift with three sources at z = 1.2–1.5 and one source at z = 3.7. Using Spitzer and Herschel observations, we estimate with good accuracy the X-ray to mid-IR (12 μm) luminosity ratio of our sources. These are well below the average AGN relation, independently suggesting that these four sources are heavily obscured.es_ES
dc.description.sponsorshipI.G. and A.C. acknowledge the Marie Curie fellowship FP7-PEOPLE-IEF-2008 Prop. 235285. We acknowledge financial contribution from the agreement ASI-INAF I/009/10/0. P.R. acknowledges the receipt of a fellowship (proposal no. P9-3493) from the Greek Secretariat of Research and Technology in the framework of the project “Support to postdoctoral researchers”. N.C. acknowledges financial support from the Della Riccia foundation. F.J.C. acknowledges partial financial support by the Spanish Ministry of Economy and Competitiveness through the grant AYA2010-21490-C02-01. The Chandra data used were taken from the Chandra Data Archive at the Chandra X-ray Center.
dc.format.extent13 p.es_ES
dc.language.isoenges_ES
dc.publisherEDP Scienceses_ES
dc.rights© ESO, 2013*
dc.sourceAstronomy and Astrophysics, 2013, 555, A43es_ES
dc.subject.otherX-rays: diffuse backgroundes_ES
dc.subject.otherInfrared: galaxieses_ES
dc.subject.otherGalaxies: activees_ES
dc.subject.otherX-rays: galaxieses_ES
dc.titleThe XMM deep survey in the CDF-S IV. Compton-thick AGN candidateses_ES
dc.typeinfo:eu-repo/semantics/articlees_ES
dc.relation.publisherVersionhttp://dx.doi.org/10.1051/0004-6361/201220828es_ES
dc.relation.publisherVersionhttps://doi.org/10.1051/0004-6361/201220828
dc.rights.accessRightsopenAccesses_ES
dc.identifier.DOI10.1051/0004-6361/201220828
dc.type.versionpublishedVersiones_ES


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