Molecular gas associated with RCW 121 and RCW 122

Autores
Arnal, Edmundo Marcelo; Duronea, Nicolás Urbano; Testori, Juan Carlos
Año de publicación
2008
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Aims. We analyse the distribution of the molecular gas towards the region containing the open cluster Havlen-Moffat 1 (HM 1) the Wolf-Rayet stars WR 87, WR 89, and WR 91, and the star forming regions RCW 121 and RCW 122, with the aim of looking for a possible physical relationship among these objects. Methods. We used the carbon monoxide observations carried out at λ ∼ 2.6 mm with the 4 m NANTEN radiotelescope; new flux density determinations derived from already existing radio continuum surveys at 2.417, 5, 8.35, and 14.35 GHz; continuum flux density determinations available in the literature; and the Midcourse Space Experiment (MSX) and the Improved Reprocessing of the IRAS Survey (IRIS) databases. Results. Adopting a distance of 5 kpc for RCW 121 and RCW 122, we found a giant molecular cloud (GMC) with a linear extent of ∼100 × 20 pc to be associated with galactic star-forming regions. The total mass of this GMC is of the order of 1.2 × 10⁶ solar masses and its mean radial velocity is about –15 km s⁻¹. Within the GMC there are individual molecular gas concentrations, having total molecular masses in the range from 4.6 × 10⁴ M⊙ (RCW 122 C) to 2.2 × 10⁵ M⊙ (RCW 122). The CO profiles observed toward the peak of the molecular concentrations are broad, with typical full-width half-maximum around 6 to 7 km s⁻¹, and show line asymmetries and/or double-peaked shape that change with the observed position within a given CO concentration. An analysis of the MSX and IRAS databases show that each CO concentration has a strong IR counterpart. The dust temperature of these concentrations range from 46 K (RCW 121) to 76 K (RCW 122 C). Their infrared luminosity are a few times 10⁵ L⊙. The new radio continuum flux density determinations are in good agreement with previous determinations at other frequencies, and confirm the thermal nature of RCW 121 and RCW 122. Based on the newly-determined 5 GHz flux density, we found that to power these Hii regions, each of them must harbour a sizable number of O type stars. Under the assumption that all the ionizing stars have a O7 V spectral type, at least ∼8 and ∼4 of these stars would be needed to ionize RCW 122 and RCW 121, respectively.
Facultad de Ciencias Astronómicas y Geofísicas
Instituto Argentino de Radioastronomía
Materia
Astronomía
ISM: molecules
radio continuum: ISM
infrared: ISM
ISM: HII regions
ISM: individual object: RCW 121
ISM: individual object: RCW 122
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:10915/123875

id SEDICI_3da2a7ca936c5d6ed1dc14097eff24e5
oai_identifier_str oai:sedici.unlp.edu.ar:10915/123875
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Molecular gas associated with RCW 121 and RCW 122Arnal, Edmundo MarceloDuronea, Nicolás UrbanoTestori, Juan CarlosAstronomíaISM: moleculesradio continuum: ISMinfrared: ISMISM: HII regionsISM: individual object: RCW 121ISM: individual object: RCW 122Aims. We analyse the distribution of the molecular gas towards the region containing the open cluster Havlen-Moffat 1 (HM 1) the Wolf-Rayet stars WR 87, WR 89, and WR 91, and the star forming regions RCW 121 and RCW 122, with the aim of looking for a possible physical relationship among these objects. Methods. We used the carbon monoxide observations carried out at λ ∼ 2.6 mm with the 4 m NANTEN radiotelescope; new flux density determinations derived from already existing radio continuum surveys at 2.417, 5, 8.35, and 14.35 GHz; continuum flux density determinations available in the literature; and the <i>Midcourse Space Experiment</i> (MSX) and the <i>Improved Reprocessing of the</i> IRAS <i>Survey</i> (IRIS) databases. Results. Adopting a distance of 5 kpc for RCW 121 and RCW 122, we found a giant molecular cloud (GMC) with a linear extent of ∼100 × 20 pc to be associated with galactic star-forming regions. The total mass of this GMC is of the order of 1.2 × 10⁶ solar masses and its mean radial velocity is about –15 km s⁻¹. Within the GMC there are individual molecular gas concentrations, having total molecular masses in the range from 4.6 × 10⁴ M⊙ (RCW 122 C) to 2.2 × 10⁵ M⊙ (RCW 122). The CO profiles observed toward the peak of the molecular concentrations are broad, with typical full-width half-maximum around 6 to 7 km s⁻¹, and show line asymmetries and/or double-peaked shape that change with the observed position within a given CO concentration. An analysis of the MSX and IRAS databases show that each CO concentration has a strong IR counterpart. The dust temperature of these concentrations range from 46 K (RCW 121) to 76 K (RCW 122 C). Their infrared luminosity are a few times 10⁵ L⊙. The new radio continuum flux density determinations are in good agreement with previous determinations at other frequencies, and confirm the thermal nature of RCW 121 and RCW 122. Based on the newly-determined 5 GHz flux density, we found that to power these Hii regions, each of them must harbour a sizable number of O type stars. Under the assumption that all the ionizing stars have a O7 V spectral type, at least ∼8 and ∼4 of these stars would be needed to ionize RCW 122 and RCW 121, respectively.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomía2008-08info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf807-818http://sedici.unlp.edu.ar/handle/10915/123875enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/issn/1432-0746info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20079126info: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:UNLP2025-09-29T11:29:24Zoai:sedici.unlp.edu.ar:10915/123875Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:29:24.812SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Molecular gas associated with RCW 121 and RCW 122
title Molecular gas associated with RCW 121 and RCW 122
spellingShingle Molecular gas associated with RCW 121 and RCW 122
Arnal, Edmundo Marcelo
Astronomía
ISM: molecules
radio continuum: ISM
infrared: ISM
ISM: HII regions
ISM: individual object: RCW 121
ISM: individual object: RCW 122
title_short Molecular gas associated with RCW 121 and RCW 122
title_full Molecular gas associated with RCW 121 and RCW 122
title_fullStr Molecular gas associated with RCW 121 and RCW 122
title_full_unstemmed Molecular gas associated with RCW 121 and RCW 122
title_sort Molecular gas associated with RCW 121 and RCW 122
dc.creator.none.fl_str_mv Arnal, Edmundo Marcelo
Duronea, Nicolás Urbano
Testori, Juan Carlos
author Arnal, Edmundo Marcelo
author_facet Arnal, Edmundo Marcelo
Duronea, Nicolás Urbano
Testori, Juan Carlos
author_role author
author2 Duronea, Nicolás Urbano
Testori, Juan Carlos
author2_role author
author
dc.subject.none.fl_str_mv Astronomía
ISM: molecules
radio continuum: ISM
infrared: ISM
ISM: HII regions
ISM: individual object: RCW 121
ISM: individual object: RCW 122
topic Astronomía
ISM: molecules
radio continuum: ISM
infrared: ISM
ISM: HII regions
ISM: individual object: RCW 121
ISM: individual object: RCW 122
dc.description.none.fl_txt_mv Aims. We analyse the distribution of the molecular gas towards the region containing the open cluster Havlen-Moffat 1 (HM 1) the Wolf-Rayet stars WR 87, WR 89, and WR 91, and the star forming regions RCW 121 and RCW 122, with the aim of looking for a possible physical relationship among these objects. Methods. We used the carbon monoxide observations carried out at λ ∼ 2.6 mm with the 4 m NANTEN radiotelescope; new flux density determinations derived from already existing radio continuum surveys at 2.417, 5, 8.35, and 14.35 GHz; continuum flux density determinations available in the literature; and the <i>Midcourse Space Experiment</i> (MSX) and the <i>Improved Reprocessing of the</i> IRAS <i>Survey</i> (IRIS) databases. Results. Adopting a distance of 5 kpc for RCW 121 and RCW 122, we found a giant molecular cloud (GMC) with a linear extent of ∼100 × 20 pc to be associated with galactic star-forming regions. The total mass of this GMC is of the order of 1.2 × 10⁶ solar masses and its mean radial velocity is about –15 km s⁻¹. Within the GMC there are individual molecular gas concentrations, having total molecular masses in the range from 4.6 × 10⁴ M⊙ (RCW 122 C) to 2.2 × 10⁵ M⊙ (RCW 122). The CO profiles observed toward the peak of the molecular concentrations are broad, with typical full-width half-maximum around 6 to 7 km s⁻¹, and show line asymmetries and/or double-peaked shape that change with the observed position within a given CO concentration. An analysis of the MSX and IRAS databases show that each CO concentration has a strong IR counterpart. The dust temperature of these concentrations range from 46 K (RCW 121) to 76 K (RCW 122 C). Their infrared luminosity are a few times 10⁵ L⊙. The new radio continuum flux density determinations are in good agreement with previous determinations at other frequencies, and confirm the thermal nature of RCW 121 and RCW 122. Based on the newly-determined 5 GHz flux density, we found that to power these Hii regions, each of them must harbour a sizable number of O type stars. Under the assumption that all the ionizing stars have a O7 V spectral type, at least ∼8 and ∼4 of these stars would be needed to ionize RCW 122 and RCW 121, respectively.
Facultad de Ciencias Astronómicas y Geofísicas
Instituto Argentino de Radioastronomía
description Aims. We analyse the distribution of the molecular gas towards the region containing the open cluster Havlen-Moffat 1 (HM 1) the Wolf-Rayet stars WR 87, WR 89, and WR 91, and the star forming regions RCW 121 and RCW 122, with the aim of looking for a possible physical relationship among these objects. Methods. We used the carbon monoxide observations carried out at λ ∼ 2.6 mm with the 4 m NANTEN radiotelescope; new flux density determinations derived from already existing radio continuum surveys at 2.417, 5, 8.35, and 14.35 GHz; continuum flux density determinations available in the literature; and the <i>Midcourse Space Experiment</i> (MSX) and the <i>Improved Reprocessing of the</i> IRAS <i>Survey</i> (IRIS) databases. Results. Adopting a distance of 5 kpc for RCW 121 and RCW 122, we found a giant molecular cloud (GMC) with a linear extent of ∼100 × 20 pc to be associated with galactic star-forming regions. The total mass of this GMC is of the order of 1.2 × 10⁶ solar masses and its mean radial velocity is about –15 km s⁻¹. Within the GMC there are individual molecular gas concentrations, having total molecular masses in the range from 4.6 × 10⁴ M⊙ (RCW 122 C) to 2.2 × 10⁵ M⊙ (RCW 122). The CO profiles observed toward the peak of the molecular concentrations are broad, with typical full-width half-maximum around 6 to 7 km s⁻¹, and show line asymmetries and/or double-peaked shape that change with the observed position within a given CO concentration. An analysis of the MSX and IRAS databases show that each CO concentration has a strong IR counterpart. The dust temperature of these concentrations range from 46 K (RCW 121) to 76 K (RCW 122 C). Their infrared luminosity are a few times 10⁵ L⊙. The new radio continuum flux density determinations are in good agreement with previous determinations at other frequencies, and confirm the thermal nature of RCW 121 and RCW 122. Based on the newly-determined 5 GHz flux density, we found that to power these Hii regions, each of them must harbour a sizable number of O type stars. Under the assumption that all the ionizing stars have a O7 V spectral type, at least ∼8 and ∼4 of these stars would be needed to ionize RCW 122 and RCW 121, respectively.
publishDate 2008
dc.date.none.fl_str_mv 2008-08
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/10915/123875
url http://sedici.unlp.edu.ar/handle/10915/123875
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/issn/1432-0746
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20079126
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
807-818
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