Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches

The spectral energy distributions (SED) of dusty galaxies at intermediate redshift may look similar to very high-redshift galaxies in the optical/near infrared (NIR) domain. This can lead to the contamination of high-redshift galaxy searches based on broad-band optical/NIR photometry by lower redshi...

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Detalhes bibliográficos
Autores: Pérez González, Pablo Guillermo, otros, ...
Formato: artículo
Fecha de publicación:2011
País:España
Recursos:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/45098
Acesso em linha:https://hdl.handle.net/20.500.14352/45098
Access Level:acceso abierto
Palavra-chave:52
Star-forming galaxies
Spectral energy-distributions
Lyman-break galaxies
Ultra-deep-field
Submillimeter galaxy
Co emission
To 7
Spectroscopic confirmation
Photometric redshifts
Massive galaxies
Astrofísica
Astronomía (Física)
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oai_identifier_str oai:docta.ucm.es:20.500.14352/45098
network_acronym_str ES
network_name_str España
repository_id_str
spelling Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searchesPérez González, Pablo Guillermootros, ...52Star-forming galaxiesSpectral energy-distributionsLyman-break galaxiesUltra-deep-fieldSubmillimeter galaxyCo emissionTo 7Spectroscopic confirmationPhotometric redshiftsMassive galaxiesAstrofísicaAstronomía (Física)The spectral energy distributions (SED) of dusty galaxies at intermediate redshift may look similar to very high-redshift galaxies in the optical/near infrared (NIR) domain. This can lead to the contamination of high-redshift galaxy searches based on broad-band optical/NIR photometry by lower redshift dusty galaxies because both kind of galaxies cannot be distinguished. The contamination rate could be as high as 50%. This work shows how the far-infrared (FIR) domain can help to recognize likely low-z interlopers in an optical/NIR search for high-z galaxies. We analyze the FIR SEDs of two galaxies that are proposed to be very high-redshift (z > 7) dropout candidates based on deep Hawk-I/VLT observations. The FIR SEDs are sampled with PACS/Herschel at 100 and 160 μm, with SPIRE/Herschel at 250, 350 and 500 μm and with LABOCA/APEX at 870 μm. We find that redshifts > 7 would imply extreme FIR SEDs (with dust temperatures >100 K and FIR luminosities >10^13 L_⊙). At z ~ 2, instead, the SEDs of both sources would be compatible with those of typical ultra luminous infrared galaxies or submillimeter galaxies. Considering all available data for these sources from visible to FIR we re-estimate the redshifts and find z ~ 1.6–2.5. Owing to the strong spectral breaks observed in these galaxies, standard templates from the literature fail to reproduce the visible-to-near-IR part of the SEDs even when additional extinction is included. These sources strongly resemble dust-obscured galaxies selected in Spitzer observations with extreme visible-to-FIR colors, and the galaxy GN10 at z = 4. Galaxies with similar SEDs could contaminate other high-redshift surveys.EDP ScienciesUniversidad Complutense de Madrid20112011-10-0120112011-10-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/45098reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/450982026-06-02T12:44:21Z
dc.title.none.fl_str_mv Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
title Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
spellingShingle Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
Pérez González, Pablo Guillermo
52
Star-forming galaxies
Spectral energy-distributions
Lyman-break galaxies
Ultra-deep-field
Submillimeter galaxy
Co emission
To 7
Spectroscopic confirmation
Photometric redshifts
Massive galaxies
Astrofísica
Astronomía (Física)
title_short Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
title_full Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
title_fullStr Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
title_full_unstemmed Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
title_sort Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches
dc.creator.none.fl_str_mv Pérez González, Pablo Guillermo
otros, ...
author Pérez González, Pablo Guillermo
author_facet Pérez González, Pablo Guillermo
otros, ...
author_role author
author2 otros, ...
author2_role author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 52
Star-forming galaxies
Spectral energy-distributions
Lyman-break galaxies
Ultra-deep-field
Submillimeter galaxy
Co emission
To 7
Spectroscopic confirmation
Photometric redshifts
Massive galaxies
Astrofísica
Astronomía (Física)
topic 52
Star-forming galaxies
Spectral energy-distributions
Lyman-break galaxies
Ultra-deep-field
Submillimeter galaxy
Co emission
To 7
Spectroscopic confirmation
Photometric redshifts
Massive galaxies
Astrofísica
Astronomía (Física)
description The spectral energy distributions (SED) of dusty galaxies at intermediate redshift may look similar to very high-redshift galaxies in the optical/near infrared (NIR) domain. This can lead to the contamination of high-redshift galaxy searches based on broad-band optical/NIR photometry by lower redshift dusty galaxies because both kind of galaxies cannot be distinguished. The contamination rate could be as high as 50%. This work shows how the far-infrared (FIR) domain can help to recognize likely low-z interlopers in an optical/NIR search for high-z galaxies. We analyze the FIR SEDs of two galaxies that are proposed to be very high-redshift (z > 7) dropout candidates based on deep Hawk-I/VLT observations. The FIR SEDs are sampled with PACS/Herschel at 100 and 160 μm, with SPIRE/Herschel at 250, 350 and 500 μm and with LABOCA/APEX at 870 μm. We find that redshifts > 7 would imply extreme FIR SEDs (with dust temperatures >100 K and FIR luminosities >10^13 L_⊙). At z ~ 2, instead, the SEDs of both sources would be compatible with those of typical ultra luminous infrared galaxies or submillimeter galaxies. Considering all available data for these sources from visible to FIR we re-estimate the redshifts and find z ~ 1.6–2.5. Owing to the strong spectral breaks observed in these galaxies, standard templates from the literature fail to reproduce the visible-to-near-IR part of the SEDs even when additional extinction is included. These sources strongly resemble dust-obscured galaxies selected in Spitzer observations with extreme visible-to-FIR colors, and the galaxy GN10 at z = 4. Galaxies with similar SEDs could contaminate other high-redshift surveys.
publishDate 2011
dc.date.none.fl_str_mv 2011
2011-10-01
2011
2011-10-01
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/20.500.14352/45098
url https://hdl.handle.net/20.500.14352/45098
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 15,301603

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