On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio

Autores
Rovero, A.C.; Donzelli, Carlos; Muriel, Hernán; Cilis, A.; Pichel, A.C.
Año de publicación
2013
Idioma
inglés
Tipo de recurso
documento de conferencia
Estado
versión publicada
Descripción
Abstract: The BL-Lac blazar PKS 0447-439 was detected at very high energy gamma-rays by HESS following the discovery by Fermi-LAT. The lack of both emission and absorption lines in BL-Lacs make the estimation of their redshifts very difficult. Modeling the drop in gamma-ray spectra it was possible to have an estimation of redshift for PKS 0447-439 of z approx 0.2, which is compatible with the value z=0.205 reported by the identification of Ca II absorption lines in optical spectra. By the identification of a weak line of Mg II using spectra with average signal-to-noise S/N approx 80, it has been recently reported a lower limit for the redshift of this blazar of z<=1.246. Triggered by this controversy, we have proposed new optical observations with the Gemini South telescope to perform further spectroscopic analysis with very high S/N ratio (approx 200-500). In this work we present a new optical spectrum of PKS 0447-439, and report on the analysis and results of such observations. Even with this significantly high quality signal we were not able to identify any spectral features to allow an estimation of the redshift. In agreement with other recent studies, we identify the Mg II line reported previously as originated in the Earth´s atmosphere, and conclude the lower limit of the redshift is incorrect. More interestingly, we could not identify the Ca II absorption lines used to report a redshift of 0.205.
Fil: Donzelli, Carlos. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.
Fil: Donzelli, Carlos. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.
Fil: Muriel, Hernán. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.
Fil: Muriel, Hernán. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.
http://adsabs.harvard.edu/abs/2013arXiv1307.6907R
Astronomía (incluye Astrofísica y Ciencias del Espacio)
Materia
Gamma-ray blazars
Gamma rays
Blazars
Optical spectroscopy
BL-Lac objects
Redshift
Nivel de accesibilidad
acceso abierto
Condiciones de uso
Repositorio
Repositorio Digital Universitario (UNC)
Institución
Universidad Nacional de Córdoba
OAI Identificador
oai:rdu.unc.edu.ar:11086/18971

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oai_identifier_str oai:rdu.unc.edu.ar:11086/18971
network_acronym_str RDUUNC
repository_id_str 2572
network_name_str Repositorio Digital Universitario (UNC)
spelling On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratioRovero, A.C.Donzelli, CarlosMuriel, HernánCilis, A.Pichel, A.C.Gamma-ray blazarsGamma raysBlazarsOptical spectroscopyBL-Lac objectsRedshiftAbstract: The BL-Lac blazar PKS 0447-439 was detected at very high energy gamma-rays by HESS following the discovery by Fermi-LAT. The lack of both emission and absorption lines in BL-Lacs make the estimation of their redshifts very difficult. Modeling the drop in gamma-ray spectra it was possible to have an estimation of redshift for PKS 0447-439 of z approx 0.2, which is compatible with the value z=0.205 reported by the identification of Ca II absorption lines in optical spectra. By the identification of a weak line of Mg II using spectra with average signal-to-noise S/N approx 80, it has been recently reported a lower limit for the redshift of this blazar of z&lt;=1.246. Triggered by this controversy, we have proposed new optical observations with the Gemini South telescope to perform further spectroscopic analysis with very high S/N ratio (approx 200-500). In this work we present a new optical spectrum of PKS 0447-439, and report on the analysis and results of such observations. Even with this significantly high quality signal we were not able to identify any spectral features to allow an estimation of the redshift. In agreement with other recent studies, we identify the Mg II line reported previously as originated in the Earth´s atmosphere, and conclude the lower limit of the redshift is incorrect. More interestingly, we could not identify the Ca II absorption lines used to report a redshift of 0.205.Fil: Donzelli, Carlos. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Donzelli, Carlos. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Muriel, Hernán. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Muriel, Hernán. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.http://adsabs.harvard.edu/abs/2013arXiv1307.6907RAstronomía (incluye Astrofísica y Ciencias del Espacio)Centro Brasileiro de Pesquisas Físicas (CBPF)2013info:eu-repo/semantics/conferenceObjectinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_5794info:ar-repo/semantics/documentoDeConferenciaapplication/pdfhttp://hdl.handle.net/11086/18971enginfo:eu-repo/semantics/openAccessreponame:Repositorio Digital Universitario (UNC)instname:Universidad Nacional de Córdobainstacron:UNC2025-09-29T13:43:08Zoai:rdu.unc.edu.ar:11086/18971Institucionalhttps://rdu.unc.edu.ar/Universidad públicaNo correspondehttp://rdu.unc.edu.ar/oai/snrdoca.unc@gmail.comArgentinaNo correspondeNo correspondeNo correspondeopendoar:25722025-09-29 13:43:08.363Repositorio Digital Universitario (UNC) - Universidad Nacional de Córdobafalse
dc.title.none.fl_str_mv On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio
title On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio
spellingShingle On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio
Rovero, A.C.
Gamma-ray blazars
Gamma rays
Blazars
Optical spectroscopy
BL-Lac objects
Redshift
title_short On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio
title_full On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio
title_fullStr On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio
title_full_unstemmed On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio
title_sort On the redshift of the gamma-ray blazar PKS 0447-439: Optical spectroscopy using Gemini observations with high S/N ratio
dc.creator.none.fl_str_mv Rovero, A.C.
Donzelli, Carlos
Muriel, Hernán
Cilis, A.
Pichel, A.C.
author Rovero, A.C.
author_facet Rovero, A.C.
Donzelli, Carlos
Muriel, Hernán
Cilis, A.
Pichel, A.C.
author_role author
author2 Donzelli, Carlos
Muriel, Hernán
Cilis, A.
Pichel, A.C.
author2_role author
author
author
author
dc.subject.none.fl_str_mv Gamma-ray blazars
Gamma rays
Blazars
Optical spectroscopy
BL-Lac objects
Redshift
topic Gamma-ray blazars
Gamma rays
Blazars
Optical spectroscopy
BL-Lac objects
Redshift
dc.description.none.fl_txt_mv Abstract: The BL-Lac blazar PKS 0447-439 was detected at very high energy gamma-rays by HESS following the discovery by Fermi-LAT. The lack of both emission and absorption lines in BL-Lacs make the estimation of their redshifts very difficult. Modeling the drop in gamma-ray spectra it was possible to have an estimation of redshift for PKS 0447-439 of z approx 0.2, which is compatible with the value z=0.205 reported by the identification of Ca II absorption lines in optical spectra. By the identification of a weak line of Mg II using spectra with average signal-to-noise S/N approx 80, it has been recently reported a lower limit for the redshift of this blazar of z&lt;=1.246. Triggered by this controversy, we have proposed new optical observations with the Gemini South telescope to perform further spectroscopic analysis with very high S/N ratio (approx 200-500). In this work we present a new optical spectrum of PKS 0447-439, and report on the analysis and results of such observations. Even with this significantly high quality signal we were not able to identify any spectral features to allow an estimation of the redshift. In agreement with other recent studies, we identify the Mg II line reported previously as originated in the Earth´s atmosphere, and conclude the lower limit of the redshift is incorrect. More interestingly, we could not identify the Ca II absorption lines used to report a redshift of 0.205.
Fil: Donzelli, Carlos. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.
Fil: Donzelli, Carlos. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.
Fil: Muriel, Hernán. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.
Fil: Muriel, Hernán. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.
http://adsabs.harvard.edu/abs/2013arXiv1307.6907R
Astronomía (incluye Astrofísica y Ciencias del Espacio)
description Abstract: The BL-Lac blazar PKS 0447-439 was detected at very high energy gamma-rays by HESS following the discovery by Fermi-LAT. The lack of both emission and absorption lines in BL-Lacs make the estimation of their redshifts very difficult. Modeling the drop in gamma-ray spectra it was possible to have an estimation of redshift for PKS 0447-439 of z approx 0.2, which is compatible with the value z=0.205 reported by the identification of Ca II absorption lines in optical spectra. By the identification of a weak line of Mg II using spectra with average signal-to-noise S/N approx 80, it has been recently reported a lower limit for the redshift of this blazar of z&lt;=1.246. Triggered by this controversy, we have proposed new optical observations with the Gemini South telescope to perform further spectroscopic analysis with very high S/N ratio (approx 200-500). In this work we present a new optical spectrum of PKS 0447-439, and report on the analysis and results of such observations. Even with this significantly high quality signal we were not able to identify any spectral features to allow an estimation of the redshift. In agreement with other recent studies, we identify the Mg II line reported previously as originated in the Earth´s atmosphere, and conclude the lower limit of the redshift is incorrect. More interestingly, we could not identify the Ca II absorption lines used to report a redshift of 0.205.
publishDate 2013
dc.date.none.fl_str_mv 2013
dc.type.none.fl_str_mv info:eu-repo/semantics/conferenceObject
info:eu-repo/semantics/publishedVersion
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info:ar-repo/semantics/documentoDeConferencia
format conferenceObject
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11086/18971
url http://hdl.handle.net/11086/18971
dc.language.none.fl_str_mv eng
language eng
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Centro Brasileiro de Pesquisas Físicas (CBPF)
publisher.none.fl_str_mv Centro Brasileiro de Pesquisas Físicas (CBPF)
dc.source.none.fl_str_mv reponame:Repositorio Digital Universitario (UNC)
instname:Universidad Nacional de Córdoba
instacron:UNC
reponame_str Repositorio Digital Universitario (UNC)
collection Repositorio Digital Universitario (UNC)
instname_str Universidad Nacional de Córdoba
instacron_str UNC
institution UNC
repository.name.fl_str_mv Repositorio Digital Universitario (UNC) - Universidad Nacional de Córdoba
repository.mail.fl_str_mv oca.unc@gmail.com
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