Radio observations of evaporating objects in the Cygnus OB2 region
- Autores
- Isequilla, Natacha Laura; Fernández López, M.; Benaglia, Paula; Ishwara Chandra, C. H.; Palacio, Santiago del
- Año de publicación
- 2019
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- We present observations of the Cygnus OB2 region obtained with the Giant Metrewave Radio Telescope (GMRT) at frequencies of 325 and 610 MHz. In this contribution we focus on the study of proplyd-like objects (also known as free-floating evaporating gas globules or frEGGs) that typically show an extended cometary morphology. We identify eight objects previously studied at other wavelengths and derive their physical properties by obtaining their optical depth at radio-wavelengths. Using their geometry and the photoionization rate needed to produce their radio-continuum emission, we find that these sources are possibly ionized by a contribution of the stars Cyg OB2 #9 and Cyg OB2 #22. Spectral index maps of the eight frEGGs were constructed, showing a flat spectrum in radio frequencies in general. We interpret these as produced by optically thin ionized gas, although it is possible that a combination of thermal emission, not necessarily optically thin, produced by a diffuse gas component and the instrument response (which detects more diffuse emission at low frequencies) can artificially generate negative spectral indices. In particular, for the case of the Tadpole we suggest that the observed emission is not of non-thermal origin despite the presence of regions with negative spectral indices in our maps.
Facultad de Ciencias Astronómicas y Geofísicas
Instituto Argentino de Radioastronomía - Materia
-
Astronomía
ISM: individual objects: Cygnus OB2
radio continuum: stars
stars: formation
stars: protostar - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by-nc-sa/4.0/
- Repositorio
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/123460
Ver los metadatos del registro completo
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Radio observations of evaporating objects in the Cygnus OB2 regionIsequilla, Natacha LauraFernández López, M.Benaglia, PaulaIshwara Chandra, C. H.Palacio, Santiago delAstronomíaISM: individual objects: Cygnus OB2radio continuum: starsstars: formationstars: protostarWe present observations of the Cygnus OB2 region obtained with the Giant Metrewave Radio Telescope (GMRT) at frequencies of 325 and 610 MHz. In this contribution we focus on the study of proplyd-like objects (also known as free-floating evaporating gas globules or frEGGs) that typically show an extended cometary morphology. We identify eight objects previously studied at other wavelengths and derive their physical properties by obtaining their optical depth at radio-wavelengths. Using their geometry and the photoionization rate needed to produce their radio-continuum emission, we find that these sources are possibly ionized by a contribution of the stars Cyg OB2 #9 and Cyg OB2 #22. Spectral index maps of the eight frEGGs were constructed, showing a flat spectrum in radio frequencies in general. We interpret these as produced by optically thin ionized gas, although it is possible that a combination of thermal emission, not necessarily optically thin, produced by a diffuse gas component and the instrument response (which detects more diffuse emission at low frequencies) can artificially generate negative spectral indices. In particular, for the case of the Tadpole we suggest that the observed emission is not of non-thermal origin despite the presence of regions with negative spectral indices in our maps.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomía2019-07info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/123460enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/issn/1432-0746info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201935179info: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:UNLP2025-09-29T11:29:28Zoai:sedici.unlp.edu.ar:10915/123460Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:29:28.804SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
Radio observations of evaporating objects in the Cygnus OB2 region |
title |
Radio observations of evaporating objects in the Cygnus OB2 region |
spellingShingle |
Radio observations of evaporating objects in the Cygnus OB2 region Isequilla, Natacha Laura Astronomía ISM: individual objects: Cygnus OB2 radio continuum: stars stars: formation stars: protostar |
title_short |
Radio observations of evaporating objects in the Cygnus OB2 region |
title_full |
Radio observations of evaporating objects in the Cygnus OB2 region |
title_fullStr |
Radio observations of evaporating objects in the Cygnus OB2 region |
title_full_unstemmed |
Radio observations of evaporating objects in the Cygnus OB2 region |
title_sort |
Radio observations of evaporating objects in the Cygnus OB2 region |
dc.creator.none.fl_str_mv |
Isequilla, Natacha Laura Fernández López, M. Benaglia, Paula Ishwara Chandra, C. H. Palacio, Santiago del |
author |
Isequilla, Natacha Laura |
author_facet |
Isequilla, Natacha Laura Fernández López, M. Benaglia, Paula Ishwara Chandra, C. H. Palacio, Santiago del |
author_role |
author |
author2 |
Fernández López, M. Benaglia, Paula Ishwara Chandra, C. H. Palacio, Santiago del |
author2_role |
author author author author |
dc.subject.none.fl_str_mv |
Astronomía ISM: individual objects: Cygnus OB2 radio continuum: stars stars: formation stars: protostar |
topic |
Astronomía ISM: individual objects: Cygnus OB2 radio continuum: stars stars: formation stars: protostar |
dc.description.none.fl_txt_mv |
We present observations of the Cygnus OB2 region obtained with the Giant Metrewave Radio Telescope (GMRT) at frequencies of 325 and 610 MHz. In this contribution we focus on the study of proplyd-like objects (also known as free-floating evaporating gas globules or frEGGs) that typically show an extended cometary morphology. We identify eight objects previously studied at other wavelengths and derive their physical properties by obtaining their optical depth at radio-wavelengths. Using their geometry and the photoionization rate needed to produce their radio-continuum emission, we find that these sources are possibly ionized by a contribution of the stars Cyg OB2 #9 and Cyg OB2 #22. Spectral index maps of the eight frEGGs were constructed, showing a flat spectrum in radio frequencies in general. We interpret these as produced by optically thin ionized gas, although it is possible that a combination of thermal emission, not necessarily optically thin, produced by a diffuse gas component and the instrument response (which detects more diffuse emission at low frequencies) can artificially generate negative spectral indices. In particular, for the case of the Tadpole we suggest that the observed emission is not of non-thermal origin despite the presence of regions with negative spectral indices in our maps. Facultad de Ciencias Astronómicas y Geofísicas Instituto Argentino de Radioastronomía |
description |
We present observations of the Cygnus OB2 region obtained with the Giant Metrewave Radio Telescope (GMRT) at frequencies of 325 and 610 MHz. In this contribution we focus on the study of proplyd-like objects (also known as free-floating evaporating gas globules or frEGGs) that typically show an extended cometary morphology. We identify eight objects previously studied at other wavelengths and derive their physical properties by obtaining their optical depth at radio-wavelengths. Using their geometry and the photoionization rate needed to produce their radio-continuum emission, we find that these sources are possibly ionized by a contribution of the stars Cyg OB2 #9 and Cyg OB2 #22. Spectral index maps of the eight frEGGs were constructed, showing a flat spectrum in radio frequencies in general. We interpret these as produced by optically thin ionized gas, although it is possible that a combination of thermal emission, not necessarily optically thin, produced by a diffuse gas component and the instrument response (which detects more diffuse emission at low frequencies) can artificially generate negative spectral indices. In particular, for the case of the Tadpole we suggest that the observed emission is not of non-thermal origin despite the presence of regions with negative spectral indices in our maps. |
publishDate |
2019 |
dc.date.none.fl_str_mv |
2019-07 |
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/10915/123460 |
url |
http://sedici.unlp.edu.ar/handle/10915/123460 |
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/10.1051/0004-6361/201935179 |
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 |
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SEDICI (UNLP) - Universidad Nacional de La Plata |
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