Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South

We identify a numerically significant population of heavily obscured AGNs at z~0.5-1 in the Chandra Deep Field-South (CDF-S) and Extended Chandra Deep Field-South by selecting 242 X-ray undetected objects with infrared-based star formation rates (SFRs) substantially higher (a factor of 3.2 or more)...

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Autores: Luo, B., Bauer, F.E.
Tipo de documento: artigo
Estado:Versão publicada
Data de publicação:2011
País:Chile
Idioma:inglês
OAI Identifier:oai:repositorio.anid.cl:10533/237310
Acesso em linha:https://hdl.handle.net/10533/237310
Access Level:Acceso aberto
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spelling Bauer, F.E.Luo, B.201110.1088/0004-637X/740/1/37https://hdl.handle.net/10533/237310http://purl.org/coar/access_right/c_abf2Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-SouthLuo, B.Bauer, F.E.2019-12-18T18:15:13Z2022-07-07T23:39:56Z2019-12-18T18:15:13Z2022-07-07T23:39:56Z2011We identify a numerically significant population of heavily obscured AGNs at z~0.5-1 in the Chandra Deep Field-South (CDF-S) and Extended Chandra Deep Field-South by selecting 242 X-ray undetected objects with infrared-based star formation rates (SFRs) substantially higher (a factor of 3.2 or more) than their SFRs determined from the UV after correcting for dust extinction. An X-ray stacking analysis of 23 candidates in the central CDF-S region using the 4 Ms Chandra data reveals a hard X-ray signal with an effective power-law photon index of Gamma=0.6_{-0.4}^{+0.3}, indicating a significant contribution from obscured AGNs. Based on Monte Carlo simulations, we conclude that 74+-25% of the selected galaxies host obscured AGNs, within which ~95% are heavily obscured and ~80% are Compton-thick (CT; NH>1.5x10^{24} cm^{-2}). The heavily obscured objects in our sample are of moderate intrinsic X-ray luminosity [ ~ (0.9-4)x10^{42} erg/s in the 2-10 keV band]. The space density of the CT AGNs is (1.6+-0.5)x10^{-4} Mpc^{-3}. The z~0.5-1 CT objects studied here are expected to contribute ~1% of the total XRB flux in the 10-30 keV band, and they account for ~5-15% of the emission in this energy band expected from all CT AGNs according to population-synthesis models. In the 6--8 keV band, the stacked signal of the 23 heavily obscured candidates accounts for <5% of the unresolved XRB flux, while the unresolved ~25% of the XRB in this band can probably be explained by a stacking analysis of the X-ray undetected optical galaxies in the CDF-S (a 2.5 sigma stacked signal). We discuss prospects to identify such heavily obscured objects using future hard X-ray observatories.FONDAPFONDAP1501000315010003virtual::19742-1WOS:000295256500037https://hdl.handle.net/10533/237310enginstname: Conicytreponame: Repositorio Digital RI2.010.1088/0004-637X/740/1/37info:eu-repo/grantAgreement/Fondap/15010003https://arxiv.org/abs/1107.3148Atribución-NoComercial-SinDerivadas 3.0 Chilehttp://creativecommons.org/licenses/by-nc-nd/3.0/cl/info:eu-repo/semantics/openAccessRevealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-SouthAstrophysical JournalArticuloinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttps://hdl.handle.net/10533/237310http://purl.org/coar/resource_type/c_2df8fbb1045fc0e1-ef55-4532-8afe-69fe789d964dvirtual::19742-1045fc0e1-ef55-4532-8afe-69fe789d964dvirtual::19742-110533/237310oai:repositorio.anid.cl:10533/2373102023-07-24 19:54:47.128https://repositorio.anid.clRepositorio ANIDaletelier@anid.cl
dc.title.none.fl_str_mv Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South
dc.title.journal.none.fl_str_mv Astrophysical Journal
title Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South
spellingShingle Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South
Luo, B.
title_short Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South
title_full Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South
title_fullStr Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South
title_full_unstemmed Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South
title_sort Revealing a Population of Heavily Obscured Active Galactic Nuclei at z=0.5-1 in the Chandra Deep Field-South
dc.creator.none.fl_str_mv Luo, B.
Bauer, F.E.
author Luo, B.
author_facet Luo, B.
Bauer, F.E.
author_role author
author2 Bauer, F.E.
author2_role author
description We identify a numerically significant population of heavily obscured AGNs at z~0.5-1 in the Chandra Deep Field-South (CDF-S) and Extended Chandra Deep Field-South by selecting 242 X-ray undetected objects with infrared-based star formation rates (SFRs) substantially higher (a factor of 3.2 or more) than their SFRs determined from the UV after correcting for dust extinction. An X-ray stacking analysis of 23 candidates in the central CDF-S region using the 4 Ms Chandra data reveals a hard X-ray signal with an effective power-law photon index of Gamma=0.6_{-0.4}^{+0.3}, indicating a significant contribution from obscured AGNs. Based on Monte Carlo simulations, we conclude that 74+-25% of the selected galaxies host obscured AGNs, within which ~95% are heavily obscured and ~80% are Compton-thick (CT; NH>1.5x10^{24} cm^{-2}). The heavily obscured objects in our sample are of moderate intrinsic X-ray luminosity [ ~ (0.9-4)x10^{42} erg/s in the 2-10 keV band]. The space density of the CT AGNs is (1.6+-0.5)x10^{-4} Mpc^{-3}. The z~0.5-1 CT objects studied here are expected to contribute ~1% of the total XRB flux in the 10-30 keV band, and they account for ~5-15% of the emission in this energy band expected from all CT AGNs according to population-synthesis models. In the 6--8 keV band, the stacked signal of the 23 heavily obscured candidates accounts for <5% of the unresolved XRB flux, while the unresolved ~25% of the XRB in this band can probably be explained by a stacking analysis of the X-ray undetected optical galaxies in the CDF-S (a 2.5 sigma stacked signal). We discuss prospects to identify such heavily obscured objects using future hard X-ray observatories.
publishDate 2011
dc.date.issued.none.fl_str_mv 2011
dc.date.accessioned.none.fl_str_mv 2019-12-18T18:15:13Z
2022-07-07T23:39:56Z
dc.date.available.none.fl_str_mv 2019-12-18T18:15:13Z
2022-07-07T23:39:56Z
dc.type.none.fl_str_mv Articulo
dc.type.driver.none.fl_str_mv info:eu-repo/semantics/article
dc.type.openaire.none.fl_str_mv info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.folio.none.fl_str_mv 15010003
15010003
dc.identifier.idwos.none.fl_str_mv WOS:000295256500037
dc.identifier.uri.none.fl_str_mv https://hdl.handle.net/10533/237310
identifier_str_mv 15010003
WOS:000295256500037
url https://hdl.handle.net/10533/237310
dc.language.iso.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv instname: Conicyt
reponame: Repositorio Digital RI2.0
dc.relation.doi.none.fl_str_mv 10.1088/0004-637X/740/1/37
dc.relation.projectid.none.fl_str_mv info:eu-repo/grantAgreement/Fondap/15010003
dc.relation.uri.none.fl_str_mv https://arxiv.org/abs/1107.3148
dc.rights.none.fl_str_mv Atribución-NoComercial-SinDerivadas 3.0 Chile
http://creativecommons.org/licenses/by-nc-nd/3.0/cl/
dc.rights.driver.none.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv Atribución-NoComercial-SinDerivadas 3.0 Chile
http://creativecommons.org/licenses/by-nc-nd/3.0/cl/
eu_rights_str_mv openAccess
repository.name.fl_str_mv Repositorio ANID
repository.mail.fl_str_mv aletelier@anid.cl
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