Circumnuclear star formation in active galaxies
Autor(a) principal: | |
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Data de Publicação: | 1996 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/108769 |
Resumo: | We study the gas kinematics and chemical abundances in the inner regions of six galaxies with active galactic nuclei. The galaxies were selected for having star-forming regions in rings or spirals within a few kiloparsecs of the nucleus. The goal of the project is to search for any connections between the gas- dynamics, the chemical abundances, and the nuclear activity. Narrowband images have been obtained to map out the ionized gas. Medium-dispersion long-slit spectroscopy at several positions over the nuclear region has been used to obtain the gaseous velocity Ðeld and distribution of excitation. The H II regions in the rings are located near the turnover point of the rotation curves, suggesting association with the inner Lindblad resonance. The nuclear ring in the LINER NGC 1326 may be located between the two inner Lindblad resonances, and the inner rings in the Seyfert 2 galaxy NGC 3081 and the LINER/ Seyfert 1 NGC 7213 may be associated with the Ω-k/4 resonance. A warm ionized medium (WIM) is found to pervade the inner region in all galaxies. There is a correlation between the [N II]/Hα and [S II]/Hα ratios and the FWHM of the [N II] λ6584 emission line in this WIM, indicating that shocks contribute to the ionization of the gas. We show that contamination by this di†use emission increases the measured [N II]/Hα and [S II]/Hα ratios at H II regions close to the nuclei and thus may account, in part, for the systematically higher [N II]/Hα and [S II]/Hα found in the present work and by previous authors for near-nuclear H II regions compared with H II regions farther out in the disk of the galaxy. In the present paper, we correct for this contamination by interpolating the contribution of the WIM at the H II regions and subtracting it o†. Oxygen and nitrogen abundances are obtained for 18 H II regions and are extrapolated to obtain the abundance of the nuclear gas, which is found to range from solar to 2 times solar for oxygen and from 2 to 4 times solar for nitrogen. Such values are similar to those observed in nonactive galaxies with the same luminosity and morphological type and do not support the idea that the central regions of active galaxies have undergone unusual chemical processing. |
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Storchi-Bergmann, ThaisaRodriguez-Ardila, AlbertoSchmitt, Henrique RobertoWilson, Andrew S.Baldwin, Jack A.2015-01-07T02:10:37Z19960004-637Xhttp://hdl.handle.net/10183/108769000178247We study the gas kinematics and chemical abundances in the inner regions of six galaxies with active galactic nuclei. The galaxies were selected for having star-forming regions in rings or spirals within a few kiloparsecs of the nucleus. The goal of the project is to search for any connections between the gas- dynamics, the chemical abundances, and the nuclear activity. Narrowband images have been obtained to map out the ionized gas. Medium-dispersion long-slit spectroscopy at several positions over the nuclear region has been used to obtain the gaseous velocity Ðeld and distribution of excitation. The H II regions in the rings are located near the turnover point of the rotation curves, suggesting association with the inner Lindblad resonance. The nuclear ring in the LINER NGC 1326 may be located between the two inner Lindblad resonances, and the inner rings in the Seyfert 2 galaxy NGC 3081 and the LINER/ Seyfert 1 NGC 7213 may be associated with the Ω-k/4 resonance. A warm ionized medium (WIM) is found to pervade the inner region in all galaxies. There is a correlation between the [N II]/Hα and [S II]/Hα ratios and the FWHM of the [N II] λ6584 emission line in this WIM, indicating that shocks contribute to the ionization of the gas. We show that contamination by this di†use emission increases the measured [N II]/Hα and [S II]/Hα ratios at H II regions close to the nuclei and thus may account, in part, for the systematically higher [N II]/Hα and [S II]/Hα found in the present work and by previous authors for near-nuclear H II regions compared with H II regions farther out in the disk of the galaxy. In the present paper, we correct for this contamination by interpolating the contribution of the WIM at the H II regions and subtracting it o†. Oxygen and nitrogen abundances are obtained for 18 H II regions and are extrapolated to obtain the abundance of the nuclear gas, which is found to range from solar to 2 times solar for oxygen and from 2 to 4 times solar for nitrogen. Such values are similar to those observed in nonactive galaxies with the same luminosity and morphological type and do not support the idea that the central regions of active galaxies have undergone unusual chemical processing.application/pdfengThe astrophysical journal. Chicago. Vol. 472, no. 1, pt. 1 (Nov. 1996), p. 83-101Galaxias seyfertFormacao de estrelasGaláxias ativasEspectros astronômicosRegioes h IINucleo galaticoGalaxies : abundancesGalaxies : activeGalaxies : ISMGalaxies : nucleiGalaxies : seyfertGalaxies : stellar contentCircumnuclear star formation in active galaxiesEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSORIGINAL000178247.pdf000178247.pdfTexto completo (inglês)application/pdf1476923http://www.lume.ufrgs.br/bitstream/10183/108769/1/000178247.pdfc9e2de4aefcae96d4e234f96ae0ad7f5MD51TEXT000178247.pdf.txt000178247.pdf.txtExtracted Texttext/plain59206http://www.lume.ufrgs.br/bitstream/10183/108769/2/000178247.pdf.txt98e71161477fd75360d7e27289c98a90MD52THUMBNAIL000178247.pdf.jpg000178247.pdf.jpgGenerated Thumbnailimage/jpeg1898http://www.lume.ufrgs.br/bitstream/10183/108769/3/000178247.pdf.jpg0fac415d3074f5967a915cb01452ac84MD5310183/1087692018-10-23 08:35:25.367oai:www.lume.ufrgs.br:10183/108769Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2018-10-23T11:35:25Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Circumnuclear star formation in active galaxies |
title |
Circumnuclear star formation in active galaxies |
spellingShingle |
Circumnuclear star formation in active galaxies Storchi-Bergmann, Thaisa Galaxias seyfert Formacao de estrelas Galáxias ativas Espectros astronômicos Regioes h II Nucleo galatico Galaxies : abundances Galaxies : active Galaxies : ISM Galaxies : nuclei Galaxies : seyfert Galaxies : stellar content |
title_short |
Circumnuclear star formation in active galaxies |
title_full |
Circumnuclear star formation in active galaxies |
title_fullStr |
Circumnuclear star formation in active galaxies |
title_full_unstemmed |
Circumnuclear star formation in active galaxies |
title_sort |
Circumnuclear star formation in active galaxies |
author |
Storchi-Bergmann, Thaisa |
author_facet |
Storchi-Bergmann, Thaisa Rodriguez-Ardila, Alberto Schmitt, Henrique Roberto Wilson, Andrew S. Baldwin, Jack A. |
author_role |
author |
author2 |
Rodriguez-Ardila, Alberto Schmitt, Henrique Roberto Wilson, Andrew S. Baldwin, Jack A. |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Storchi-Bergmann, Thaisa Rodriguez-Ardila, Alberto Schmitt, Henrique Roberto Wilson, Andrew S. Baldwin, Jack A. |
dc.subject.por.fl_str_mv |
Galaxias seyfert Formacao de estrelas Galáxias ativas Espectros astronômicos Regioes h II Nucleo galatico |
topic |
Galaxias seyfert Formacao de estrelas Galáxias ativas Espectros astronômicos Regioes h II Nucleo galatico Galaxies : abundances Galaxies : active Galaxies : ISM Galaxies : nuclei Galaxies : seyfert Galaxies : stellar content |
dc.subject.eng.fl_str_mv |
Galaxies : abundances Galaxies : active Galaxies : ISM Galaxies : nuclei Galaxies : seyfert Galaxies : stellar content |
description |
We study the gas kinematics and chemical abundances in the inner regions of six galaxies with active galactic nuclei. The galaxies were selected for having star-forming regions in rings or spirals within a few kiloparsecs of the nucleus. The goal of the project is to search for any connections between the gas- dynamics, the chemical abundances, and the nuclear activity. Narrowband images have been obtained to map out the ionized gas. Medium-dispersion long-slit spectroscopy at several positions over the nuclear region has been used to obtain the gaseous velocity Ðeld and distribution of excitation. The H II regions in the rings are located near the turnover point of the rotation curves, suggesting association with the inner Lindblad resonance. The nuclear ring in the LINER NGC 1326 may be located between the two inner Lindblad resonances, and the inner rings in the Seyfert 2 galaxy NGC 3081 and the LINER/ Seyfert 1 NGC 7213 may be associated with the Ω-k/4 resonance. A warm ionized medium (WIM) is found to pervade the inner region in all galaxies. There is a correlation between the [N II]/Hα and [S II]/Hα ratios and the FWHM of the [N II] λ6584 emission line in this WIM, indicating that shocks contribute to the ionization of the gas. We show that contamination by this di†use emission increases the measured [N II]/Hα and [S II]/Hα ratios at H II regions close to the nuclei and thus may account, in part, for the systematically higher [N II]/Hα and [S II]/Hα found in the present work and by previous authors for near-nuclear H II regions compared with H II regions farther out in the disk of the galaxy. In the present paper, we correct for this contamination by interpolating the contribution of the WIM at the H II regions and subtracting it o†. Oxygen and nitrogen abundances are obtained for 18 H II regions and are extrapolated to obtain the abundance of the nuclear gas, which is found to range from solar to 2 times solar for oxygen and from 2 to 4 times solar for nitrogen. Such values are similar to those observed in nonactive galaxies with the same luminosity and morphological type and do not support the idea that the central regions of active galaxies have undergone unusual chemical processing. |
publishDate |
1996 |
dc.date.issued.fl_str_mv |
1996 |
dc.date.accessioned.fl_str_mv |
2015-01-07T02:10:37Z |
dc.type.driver.fl_str_mv |
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info:eu-repo/semantics/publishedVersion |
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http://hdl.handle.net/10183/108769 |
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0004-637X |
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000178247 |
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url |
http://hdl.handle.net/10183/108769 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
The astrophysical journal. Chicago. Vol. 472, no. 1, pt. 1 (Nov. 1996), p. 83-101 |
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openAccess |
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