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
- Institución
- Universidad Nacional de Córdoba
- OAI Identificador
- oai:rdu.unc.edu.ar:11086/18971
Ver los metadatos del registro completo
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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<=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<=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<=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 http://purl.org/coar/resource_type/c_5794 info:ar-repo/semantics/documentoDeConferencia |
format |
conferenceObject |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://hdl.handle.net/11086/18971 |
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http://hdl.handle.net/11086/18971 |
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eng |
language |
eng |
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openAccess |
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application/pdf |
dc.publisher.none.fl_str_mv |
Centro Brasileiro de Pesquisas Físicas (CBPF) |
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Centro Brasileiro de Pesquisas Físicas (CBPF) |
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Repositorio Digital Universitario (UNC) - Universidad Nacional de Córdoba |
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oca.unc@gmail.com |
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