The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies

Context. Accretion onto supermassive black holes is believed to occur mostly in obscured active galactic nuclei (AGN). Such objects are proving rather elusive in surveys of distant galaxies, including those at X-ray energies. Aims. Our main goal is to determine whether the revised IRAC criteria of D...

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Autores: Castelló Mor, N., Carrera, F. J., Alonso Herrero, A., Mateos, S., Barcons, X., Ranalli, P., Pérez González, Pablo Guillermo, Comastri, A., Vignali, C., Georgantopoulos, I.
Tipo de recurso: artículo
Fecha de publicación:2013
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/35208
Acceso en línea:https://hdl.handle.net/20.500.14352/35208
Access Level:acceso abierto
Palabra clave:52
Active galactic nuclei
Spitzer-space-telescope
Spectral energy-distribution
Quasi-stellar objects
Star-forming galaxies
Field-south survey
X-ray sources
Midinfrared selection
Synthesis models
Source catalogs
Astrofísica
Astronomía (Física)
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oai_identifier_str oai:docta.ucm.es:20.500.14352/35208
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repository_id_str
spelling The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxiesCastelló Mor, N.Carrera, F. J.Alonso Herrero, A.Mateos, S.Barcons, X.Ranalli, P.Pérez González, Pablo GuillermoComastri, A.Vignali, C.Georgantopoulos, I.52Active galactic nucleiSpitzer-space-telescopeSpectral energy-distributionQuasi-stellar objectsStar-forming galaxiesField-south surveyX-ray sourcesMidinfrared selectionSynthesis modelsSource catalogsAstrofísicaAstronomía (Física)Context. Accretion onto supermassive black holes is believed to occur mostly in obscured active galactic nuclei (AGN). Such objects are proving rather elusive in surveys of distant galaxies, including those at X-ray energies. Aims. Our main goal is to determine whether the revised IRAC criteria of Donley et al. (2012, ApJ, 748, 142; objects with an infrared (IR) power-law spectral shape), are effective at selecting X-ray type-2 AGN (i.e., absorbed N_H > 10^22 cm^-2). Methods. We present the results from the X-ray spectral analysis of 147 AGN selected by cross-correlating the highest spectral quality ultra-deep XMM-Newton and the Spitzer/IRAC catalogues in the Chandra Deep Field South. Consequently it is biased towards sources with high S/N X-ray spectra. In order to measure the amount of intrinsic absorption in these sources, we adopt a simple X-ray spectral model that includes a power-law modified by intrinsic absorption at the redshift of each source and a possible soft X-ray component. Results. We find 21/147 sources to be heavily absorbed but the uncertainties in their obscuring column densities do not allow us to confirm their Compton-Thick nature without resorting to additional criteria. Although IR power-law galaxies are less numerous in our sample than IR non-power-law galaxies (60 versus 87 respectively), we find that the fraction of absorbed (N_H^intr > 10^22 cm^-2) AGN is significantly higher (at about 3 sigma level) for IR-power-law sources (similar to 2/3) than for those sources that do not meet this IR selection criteria (~1/2). This behaviour is particularly notable at low luminosities, but it appears to be present, although with a marginal significance, at all luminosities. Conclusions. We therefore conclude that the IR power-law method is efficient in finding X-ray-absorbed sources. We would then expect that the long-sought dominant population of absorbed AGN is abundant among IR power-law spectral shape sources not detected in X-rays.EDP ScienciesUniversidad Complutense de Madrid20132013-08-0120132013-08-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/35208reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/352082026-06-02T12:44:21Z
dc.title.none.fl_str_mv The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies
title The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies
spellingShingle The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies
Castelló Mor, N.
52
Active galactic nuclei
Spitzer-space-telescope
Spectral energy-distribution
Quasi-stellar objects
Star-forming galaxies
Field-south survey
X-ray sources
Midinfrared selection
Synthesis models
Source catalogs
Astrofísica
Astronomía (Física)
title_short The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies
title_full The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies
title_fullStr The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies
title_full_unstemmed The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies
title_sort The XMM deep survey in the CDF-S. VI. Obscured AGN selected as infrared power-law galaxies
dc.creator.none.fl_str_mv Castelló Mor, N.
Carrera, F. J.
Alonso Herrero, A.
Mateos, S.
Barcons, X.
Ranalli, P.
Pérez González, Pablo Guillermo
Comastri, A.
Vignali, C.
Georgantopoulos, I.
author Castelló Mor, N.
author_facet Castelló Mor, N.
Carrera, F. J.
Alonso Herrero, A.
Mateos, S.
Barcons, X.
Ranalli, P.
Pérez González, Pablo Guillermo
Comastri, A.
Vignali, C.
Georgantopoulos, I.
author_role author
author2 Carrera, F. J.
Alonso Herrero, A.
Mateos, S.
Barcons, X.
Ranalli, P.
Pérez González, Pablo Guillermo
Comastri, A.
Vignali, C.
Georgantopoulos, I.
author2_role author
author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 52
Active galactic nuclei
Spitzer-space-telescope
Spectral energy-distribution
Quasi-stellar objects
Star-forming galaxies
Field-south survey
X-ray sources
Midinfrared selection
Synthesis models
Source catalogs
Astrofísica
Astronomía (Física)
topic 52
Active galactic nuclei
Spitzer-space-telescope
Spectral energy-distribution
Quasi-stellar objects
Star-forming galaxies
Field-south survey
X-ray sources
Midinfrared selection
Synthesis models
Source catalogs
Astrofísica
Astronomía (Física)
description Context. Accretion onto supermassive black holes is believed to occur mostly in obscured active galactic nuclei (AGN). Such objects are proving rather elusive in surveys of distant galaxies, including those at X-ray energies. Aims. Our main goal is to determine whether the revised IRAC criteria of Donley et al. (2012, ApJ, 748, 142; objects with an infrared (IR) power-law spectral shape), are effective at selecting X-ray type-2 AGN (i.e., absorbed N_H > 10^22 cm^-2). Methods. We present the results from the X-ray spectral analysis of 147 AGN selected by cross-correlating the highest spectral quality ultra-deep XMM-Newton and the Spitzer/IRAC catalogues in the Chandra Deep Field South. Consequently it is biased towards sources with high S/N X-ray spectra. In order to measure the amount of intrinsic absorption in these sources, we adopt a simple X-ray spectral model that includes a power-law modified by intrinsic absorption at the redshift of each source and a possible soft X-ray component. Results. We find 21/147 sources to be heavily absorbed but the uncertainties in their obscuring column densities do not allow us to confirm their Compton-Thick nature without resorting to additional criteria. Although IR power-law galaxies are less numerous in our sample than IR non-power-law galaxies (60 versus 87 respectively), we find that the fraction of absorbed (N_H^intr > 10^22 cm^-2) AGN is significantly higher (at about 3 sigma level) for IR-power-law sources (similar to 2/3) than for those sources that do not meet this IR selection criteria (~1/2). This behaviour is particularly notable at low luminosities, but it appears to be present, although with a marginal significance, at all luminosities. Conclusions. We therefore conclude that the IR power-law method is efficient in finding X-ray-absorbed sources. We would then expect that the long-sought dominant population of absorbed AGN is abundant among IR power-law spectral shape sources not detected in X-rays.
publishDate 2013
dc.date.none.fl_str_mv 2013
2013-08-01
2013
2013-08-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/20.500.14352/35208
url https://hdl.handle.net/20.500.14352/35208
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv EDP Sciencies
publisher.none.fl_str_mv EDP Sciencies
dc.source.none.fl_str_mv reponame:Docta Complutense
instname:Universidad Complutense de Madrid (UCM)
instname_str Universidad Complutense de Madrid (UCM)
reponame_str Docta Complutense
collection Docta Complutense
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,300719

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