Multiwavelength studies of WR 21a and its surroundings

Autores
Benaglia, Paula; Romero, Gustavo Esteban; Koribalski, B.; Pollock, A. M.T.
Año de publicación
2005
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We present results of high-resolution radio continuum observations towards the binary star WR 21a (Wack 2134) obtained with the Australia Telescope Compact Array (ATCA**) at 4.8 and 8.64 GHz. We detected the system at 4.8 GHz (6 cm) with a flux density of 0.25 ± 0.06 mJy and set an upper limit of 0.3 mJy at 8.64 GHz (3 cm). The derived spectral index of α < 0.3 (S v ∝ v α ) suggests the presence of non-thermal emission, probably originating in a colliding-wind region. A second, unrelated radio source was detected ∼10″ north of WR 21a at (RA, Dec) J2000 = (10 h 25 m 56 s .49, -57°48′34.4″), with flux densities of 0.36 and 0.55 mJy at 4.8 and 8.64 GHz, respectively, resulting in α = 0.72. H I observations in the area are dominated by absorption against the prominent H II region RCW 49. Analysis of a complete set of archived X-ray observations of WR 21a confirms its strong variability but throws into doubt previous suggestions by Reig (1999) of a period of years for the system. Finally, we comment on the association with the nearby EGRET source 3EG J1027-5817.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
Gamma-rays: observations
ISM: bubbles
Radio continuum: stars
Stars: early-type
Stars: individual: WR 21a
Stars: winds, outflows
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/83278

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oai_identifier_str oai:sedici.unlp.edu.ar:10915/83278
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Multiwavelength studies of WR 21a and its surroundingsBenaglia, PaulaRomero, Gustavo EstebanKoribalski, B.Pollock, A. M.T.Ciencias AstronómicasGamma-rays: observationsISM: bubblesRadio continuum: starsStars: early-typeStars: individual: WR 21aStars: winds, outflowsWe present results of high-resolution radio continuum observations towards the binary star WR 21a (Wack 2134) obtained with the Australia Telescope Compact Array (ATCA**) at 4.8 and 8.64 GHz. We detected the system at 4.8 GHz (6 cm) with a flux density of 0.25 ± 0.06 mJy and set an upper limit of 0.3 mJy at 8.64 GHz (3 cm). The derived spectral index of α < 0.3 (S v ∝ v α ) suggests the presence of non-thermal emission, probably originating in a colliding-wind region. A second, unrelated radio source was detected ∼10″ north of WR 21a at (RA, Dec) J2000 = (10 h 25 m 56 s .49, -57°48′34.4″), with flux densities of 0.36 and 0.55 mJy at 4.8 and 8.64 GHz, respectively, resulting in α = 0.72. H I observations in the area are dominated by absorption against the prominent H II region RCW 49. Analysis of a complete set of archived X-ray observations of WR 21a confirms its strong variability but throws into doubt previous suggestions by Reig (1999) of a period of years for the system. Finally, we comment on the association with the nearby EGRET source 3EG J1027-5817.Facultad de Ciencias Astronómicas y Geofísicas2005info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf743-750http://sedici.unlp.edu.ar/handle/10915/83278enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20042617info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:15:46Zoai:sedici.unlp.edu.ar:10915/83278Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:46.914SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Multiwavelength studies of WR 21a and its surroundings
title Multiwavelength studies of WR 21a and its surroundings
spellingShingle Multiwavelength studies of WR 21a and its surroundings
Benaglia, Paula
Ciencias Astronómicas
Gamma-rays: observations
ISM: bubbles
Radio continuum: stars
Stars: early-type
Stars: individual: WR 21a
Stars: winds, outflows
title_short Multiwavelength studies of WR 21a and its surroundings
title_full Multiwavelength studies of WR 21a and its surroundings
title_fullStr Multiwavelength studies of WR 21a and its surroundings
title_full_unstemmed Multiwavelength studies of WR 21a and its surroundings
title_sort Multiwavelength studies of WR 21a and its surroundings
dc.creator.none.fl_str_mv Benaglia, Paula
Romero, Gustavo Esteban
Koribalski, B.
Pollock, A. M.T.
author Benaglia, Paula
author_facet Benaglia, Paula
Romero, Gustavo Esteban
Koribalski, B.
Pollock, A. M.T.
author_role author
author2 Romero, Gustavo Esteban
Koribalski, B.
Pollock, A. M.T.
author2_role author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Gamma-rays: observations
ISM: bubbles
Radio continuum: stars
Stars: early-type
Stars: individual: WR 21a
Stars: winds, outflows
topic Ciencias Astronómicas
Gamma-rays: observations
ISM: bubbles
Radio continuum: stars
Stars: early-type
Stars: individual: WR 21a
Stars: winds, outflows
dc.description.none.fl_txt_mv We present results of high-resolution radio continuum observations towards the binary star WR 21a (Wack 2134) obtained with the Australia Telescope Compact Array (ATCA**) at 4.8 and 8.64 GHz. We detected the system at 4.8 GHz (6 cm) with a flux density of 0.25 ± 0.06 mJy and set an upper limit of 0.3 mJy at 8.64 GHz (3 cm). The derived spectral index of α < 0.3 (S v ∝ v α ) suggests the presence of non-thermal emission, probably originating in a colliding-wind region. A second, unrelated radio source was detected ∼10″ north of WR 21a at (RA, Dec) J2000 = (10 h 25 m 56 s .49, -57°48′34.4″), with flux densities of 0.36 and 0.55 mJy at 4.8 and 8.64 GHz, respectively, resulting in α = 0.72. H I observations in the area are dominated by absorption against the prominent H II region RCW 49. Analysis of a complete set of archived X-ray observations of WR 21a confirms its strong variability but throws into doubt previous suggestions by Reig (1999) of a period of years for the system. Finally, we comment on the association with the nearby EGRET source 3EG J1027-5817.
Facultad de Ciencias Astronómicas y Geofísicas
description We present results of high-resolution radio continuum observations towards the binary star WR 21a (Wack 2134) obtained with the Australia Telescope Compact Array (ATCA**) at 4.8 and 8.64 GHz. We detected the system at 4.8 GHz (6 cm) with a flux density of 0.25 ± 0.06 mJy and set an upper limit of 0.3 mJy at 8.64 GHz (3 cm). The derived spectral index of α < 0.3 (S v ∝ v α ) suggests the presence of non-thermal emission, probably originating in a colliding-wind region. A second, unrelated radio source was detected ∼10″ north of WR 21a at (RA, Dec) J2000 = (10 h 25 m 56 s .49, -57°48′34.4″), with flux densities of 0.36 and 0.55 mJy at 4.8 and 8.64 GHz, respectively, resulting in α = 0.72. H I observations in the area are dominated by absorption against the prominent H II region RCW 49. Analysis of a complete set of archived X-ray observations of WR 21a confirms its strong variability but throws into doubt previous suggestions by Reig (1999) of a period of years for the system. Finally, we comment on the association with the nearby EGRET source 3EG J1027-5817.
publishDate 2005
dc.date.none.fl_str_mv 2005
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/83278
url http://sedici.unlp.edu.ar/handle/10915/83278
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0004-6361
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20042617
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
743-750
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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