Empirical diagnostics of the starburst-AGN connection
Autor(a) principal: | |
---|---|
Data de Publicação: | 2001 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/108884 |
Resumo: | We examine a representative sample of 35 Seyfert 2 nuclei. Previous work has shown that nearly half (15) of these nuclei show the direct (but difficult to detect) spectroscopic signature at optical/near-UV wavelengths of the hot massive stars that power circumnuclear starbursts. In the present paper we examine a variety of more easily measured quantities for this sample, such as the equivalent widths of strong absorption features, continuum colors, emission line equivalent widths, emission line ratios and proÐles, far-IR luminosities, and near-UV surface brightness. We compare the composite starburst + Seyfert 2 nuclei to "pure" Seyfert 2 nuclei, Starburst galaxies, and normal galactic nuclei. Our goals are to verify whether the easily measured properties of the composite nuclei are consistent with the expected impact of a starburst and to investigate alternative less demanding methods to infer the presence of starbursts in Seyfert 2 nuclei, applicable to larger or more distant samples. We show that starbursts do indeed leave clear and easily quantiÐable imprints on the near-UV to optical continuum and emission line properties of Seyfert 2's. Composite starburst + Seyfert 2 systems can be recognized by: (1) a strong "featureless continuum" (FC), which dilutes the Ca II K line from old stars in the host's bulge to an equivalent width WK<10 Å; (2) emission lines whose equivalent widths are intermediate between starburst galaxies and "pure" Seyfert 2's ; (3) relatively low excitation line ratios, which indicate that part of the gas ionization in these Seyfert 2's (typically ~50% of Hβ) is due to photoionization by OB stars ; (4) large far-IR luminosities (>~10 10 Lʘ; (5) high near-UV surface brightness (~10 3 Lʘ pc-²). These characteristics are all consistent with the expected impact of circumnuclear starbursts on the observed properties of Seyfert 2's. Furthermore, they oer alternative empirical diagnostics of the presence of circumnuclear starbursts from a few easily measured quantities. |
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Fernandes Junior, Roberto CidHeckman, Timothy M.Schmitt, Henrique RobertoGonzález Delgado, Rosa M.Storchi-Bergmann, Thaisa2015-01-13T02:14:40Z20010004-637Xhttp://hdl.handle.net/10183/108884000306126We examine a representative sample of 35 Seyfert 2 nuclei. Previous work has shown that nearly half (15) of these nuclei show the direct (but difficult to detect) spectroscopic signature at optical/near-UV wavelengths of the hot massive stars that power circumnuclear starbursts. In the present paper we examine a variety of more easily measured quantities for this sample, such as the equivalent widths of strong absorption features, continuum colors, emission line equivalent widths, emission line ratios and proÐles, far-IR luminosities, and near-UV surface brightness. We compare the composite starburst + Seyfert 2 nuclei to "pure" Seyfert 2 nuclei, Starburst galaxies, and normal galactic nuclei. Our goals are to verify whether the easily measured properties of the composite nuclei are consistent with the expected impact of a starburst and to investigate alternative less demanding methods to infer the presence of starbursts in Seyfert 2 nuclei, applicable to larger or more distant samples. We show that starbursts do indeed leave clear and easily quantiÐable imprints on the near-UV to optical continuum and emission line properties of Seyfert 2's. Composite starburst + Seyfert 2 systems can be recognized by: (1) a strong "featureless continuum" (FC), which dilutes the Ca II K line from old stars in the host's bulge to an equivalent width WK<10 Å; (2) emission lines whose equivalent widths are intermediate between starburst galaxies and "pure" Seyfert 2's ; (3) relatively low excitation line ratios, which indicate that part of the gas ionization in these Seyfert 2's (typically ~50% of Hβ) is due to photoionization by OB stars ; (4) large far-IR luminosities (>~10 10 Lʘ; (5) high near-UV surface brightness (~10 3 Lʘ pc-²). These characteristics are all consistent with the expected impact of circumnuclear starbursts on the observed properties of Seyfert 2's. Furthermore, they oer alternative empirical diagnostics of the presence of circumnuclear starbursts from a few easily measured quantities.application/pdfengThe astrophysical journal. Chicago. Vol. 558, no. 1 pt. 1 (Sept. 2001), p. 81-108Fotometria astronômicaEspectros astronômicosNucleo galaticoFontes de infravermelhoMateria interestelarGalaxias seyfertFormacao de estrelasGHalaxies : activeGalaxies : nucleiGalaxies : SeyfertEmpirical diagnostics of the starburst-AGN connectionEstrangeiroinfo: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:UFRGSORIGINAL000306126.pdf000306126.pdfTexto completo (inglês)application/pdf449374http://www.lume.ufrgs.br/bitstream/10183/108884/1/000306126.pdfce4867a4d1a32e2030d46b3876d222eaMD51TEXT000306126.pdf.txt000306126.pdf.txtExtracted Texttext/plain148947http://www.lume.ufrgs.br/bitstream/10183/108884/2/000306126.pdf.txt71a41cb7685a001b43d5c8e6bea8c7bfMD52THUMBNAIL000306126.pdf.jpg000306126.pdf.jpgGenerated Thumbnailimage/jpeg2196http://www.lume.ufrgs.br/bitstream/10183/108884/3/000306126.pdf.jpg0eefa5de6c09f6502235523d220d729fMD5310183/1088842018-10-23 08:38:14.307oai:www.lume.ufrgs.br:10183/108884Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2018-10-23T11:38:14Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Empirical diagnostics of the starburst-AGN connection |
title |
Empirical diagnostics of the starburst-AGN connection |
spellingShingle |
Empirical diagnostics of the starburst-AGN connection Fernandes Junior, Roberto Cid Fotometria astronômica Espectros astronômicos Nucleo galatico Fontes de infravermelho Materia interestelar Galaxias seyfert Formacao de estrelas GHalaxies : active Galaxies : nuclei Galaxies : Seyfert |
title_short |
Empirical diagnostics of the starburst-AGN connection |
title_full |
Empirical diagnostics of the starburst-AGN connection |
title_fullStr |
Empirical diagnostics of the starburst-AGN connection |
title_full_unstemmed |
Empirical diagnostics of the starburst-AGN connection |
title_sort |
Empirical diagnostics of the starburst-AGN connection |
author |
Fernandes Junior, Roberto Cid |
author_facet |
Fernandes Junior, Roberto Cid Heckman, Timothy M. Schmitt, Henrique Roberto González Delgado, Rosa M. Storchi-Bergmann, Thaisa |
author_role |
author |
author2 |
Heckman, Timothy M. Schmitt, Henrique Roberto González Delgado, Rosa M. Storchi-Bergmann, Thaisa |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Fernandes Junior, Roberto Cid Heckman, Timothy M. Schmitt, Henrique Roberto González Delgado, Rosa M. Storchi-Bergmann, Thaisa |
dc.subject.por.fl_str_mv |
Fotometria astronômica Espectros astronômicos Nucleo galatico Fontes de infravermelho Materia interestelar Galaxias seyfert Formacao de estrelas |
topic |
Fotometria astronômica Espectros astronômicos Nucleo galatico Fontes de infravermelho Materia interestelar Galaxias seyfert Formacao de estrelas GHalaxies : active Galaxies : nuclei Galaxies : Seyfert |
dc.subject.eng.fl_str_mv |
GHalaxies : active Galaxies : nuclei Galaxies : Seyfert |
description |
We examine a representative sample of 35 Seyfert 2 nuclei. Previous work has shown that nearly half (15) of these nuclei show the direct (but difficult to detect) spectroscopic signature at optical/near-UV wavelengths of the hot massive stars that power circumnuclear starbursts. In the present paper we examine a variety of more easily measured quantities for this sample, such as the equivalent widths of strong absorption features, continuum colors, emission line equivalent widths, emission line ratios and proÐles, far-IR luminosities, and near-UV surface brightness. We compare the composite starburst + Seyfert 2 nuclei to "pure" Seyfert 2 nuclei, Starburst galaxies, and normal galactic nuclei. Our goals are to verify whether the easily measured properties of the composite nuclei are consistent with the expected impact of a starburst and to investigate alternative less demanding methods to infer the presence of starbursts in Seyfert 2 nuclei, applicable to larger or more distant samples. We show that starbursts do indeed leave clear and easily quantiÐable imprints on the near-UV to optical continuum and emission line properties of Seyfert 2's. Composite starburst + Seyfert 2 systems can be recognized by: (1) a strong "featureless continuum" (FC), which dilutes the Ca II K line from old stars in the host's bulge to an equivalent width WK<10 Å; (2) emission lines whose equivalent widths are intermediate between starburst galaxies and "pure" Seyfert 2's ; (3) relatively low excitation line ratios, which indicate that part of the gas ionization in these Seyfert 2's (typically ~50% of Hβ) is due to photoionization by OB stars ; (4) large far-IR luminosities (>~10 10 Lʘ; (5) high near-UV surface brightness (~10 3 Lʘ pc-²). These characteristics are all consistent with the expected impact of circumnuclear starbursts on the observed properties of Seyfert 2's. Furthermore, they oer alternative empirical diagnostics of the presence of circumnuclear starbursts from a few easily measured quantities. |
publishDate |
2001 |
dc.date.issued.fl_str_mv |
2001 |
dc.date.accessioned.fl_str_mv |
2015-01-13T02:14:40Z |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/108884 |
dc.identifier.issn.pt_BR.fl_str_mv |
0004-637X |
dc.identifier.nrb.pt_BR.fl_str_mv |
000306126 |
identifier_str_mv |
0004-637X 000306126 |
url |
http://hdl.handle.net/10183/108884 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
The astrophysical journal. Chicago. Vol. 558, no. 1 pt. 1 (Sept. 2001), p. 81-108 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
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