On warmers as the ionizing source in active galactic nuclei

Detalhes bibliográficos
Autor(a) principal: Fernandes Junior, Roberto Cid
Data de Publicação: 1992
Outros Autores: Dottori, Horacio Alberto, Gruenwald, Ruth B., Viegas, Sueli Maria Marino
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UFRGS
Texto Completo: http://hdl.handle.net/10183/88376
Resumo: The aim of this paper is to study in detail the Terlevich & Melnick starburst-warmers scenario for type 2 Seyferts and LINERs, which postulates a young cluster containing stars with temperatures about 150 000 K as the heating source in these objects. A numerical code was developed to compute the total spectrum of a star cluster given its age and initial mass function. The ionizing spectra so obtained were used in the photoionization code AANGABA to calculate the nebular ernission-line spectra for a grid of cloud parameters covering different densities (and gradients), ionization parameters and metallicities. The evolution of the system was followed on classical diagnostic diagrams and a very good agreement with Terlevich & Melnick's results was found. We conclude that warmers can indeed be the ionizing source in many narrow-line AGN, although the coverage of AGN areas on diagnostic diagrams is not complete. We find the warmers model successful within a metallicity range between ~~0.5 and 2Z̛. The upper limit is set by the strong cloud cooling by forbidden lines. On the other hand, at Z<~0.5 Z̛ fewer stars would be thrown into 'warmer' phases due to the smaller mass-loss rates, and even if warmers occur the ernission-line spectrum would correspond to an H II galaxy rather than to an AGN. The chernical pollution of the gas by the strongly processed stellar winds of massive stars is also studied. Our results suggest that the nitrogen overabundance of AGN frequently claimed in the literature arises quite naturally in this scenario.
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spelling Fernandes Junior, Roberto CidDottori, Horacio AlbertoGruenwald, Ruth B.Viegas, Sueli Maria Marino2014-03-13T01:50:40Z19920035-8711http://hdl.handle.net/10183/88376000056053The aim of this paper is to study in detail the Terlevich & Melnick starburst-warmers scenario for type 2 Seyferts and LINERs, which postulates a young cluster containing stars with temperatures about 150 000 K as the heating source in these objects. A numerical code was developed to compute the total spectrum of a star cluster given its age and initial mass function. The ionizing spectra so obtained were used in the photoionization code AANGABA to calculate the nebular ernission-line spectra for a grid of cloud parameters covering different densities (and gradients), ionization parameters and metallicities. The evolution of the system was followed on classical diagnostic diagrams and a very good agreement with Terlevich & Melnick's results was found. We conclude that warmers can indeed be the ionizing source in many narrow-line AGN, although the coverage of AGN areas on diagnostic diagrams is not complete. We find the warmers model successful within a metallicity range between ~~0.5 and 2Z̛. The upper limit is set by the strong cloud cooling by forbidden lines. On the other hand, at Z<~0.5 Z̛ fewer stars would be thrown into 'warmer' phases due to the smaller mass-loss rates, and even if warmers occur the ernission-line spectrum would correspond to an H II galaxy rather than to an AGN. The chernical pollution of the gas by the strongly processed stellar winds of massive stars is also studied. Our results suggest that the nitrogen overabundance of AGN frequently claimed in the literature arises quite naturally in this scenario.application/pdfengMonthly Notices of the Royal Astronomical Society. London. Vol. 255, no. 1 (Mar. 1992), p. 165-176Astrofisica extragalaticaAstronomia e astrofisicaGalaxias seyfertMetalicidadeOn warmers as the ionizing source in active galactic nucleiEstrangeiroinfo: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:UFRGSORIGINAL000056053.pdf000056053.pdfTexto completo (inglês)application/pdf372482http://www.lume.ufrgs.br/bitstream/10183/88376/1/000056053.pdf57bc0bff18fb079ca3f8845be170f983MD51TEXT000056053.pdf.txt000056053.pdf.txtExtracted Texttext/plain264http://www.lume.ufrgs.br/bitstream/10183/88376/2/000056053.pdf.txt4cdeaad41a000b1e0dc6a6654cf5f737MD52THUMBNAIL000056053.pdf.jpg000056053.pdf.jpgGenerated Thumbnailimage/jpeg1976http://www.lume.ufrgs.br/bitstream/10183/88376/3/000056053.pdf.jpge7024e6251c23a640f9eeae4855e53ccMD5310183/883762018-10-18 08:18:09.34oai:www.lume.ufrgs.br:10183/88376Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2018-10-18T11:18:09Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false
dc.title.pt_BR.fl_str_mv On warmers as the ionizing source in active galactic nuclei
title On warmers as the ionizing source in active galactic nuclei
spellingShingle On warmers as the ionizing source in active galactic nuclei
Fernandes Junior, Roberto Cid
Astrofisica extragalatica
Astronomia e astrofisica
Galaxias seyfert
Metalicidade
title_short On warmers as the ionizing source in active galactic nuclei
title_full On warmers as the ionizing source in active galactic nuclei
title_fullStr On warmers as the ionizing source in active galactic nuclei
title_full_unstemmed On warmers as the ionizing source in active galactic nuclei
title_sort On warmers as the ionizing source in active galactic nuclei
author Fernandes Junior, Roberto Cid
author_facet Fernandes Junior, Roberto Cid
Dottori, Horacio Alberto
Gruenwald, Ruth B.
Viegas, Sueli Maria Marino
author_role author
author2 Dottori, Horacio Alberto
Gruenwald, Ruth B.
Viegas, Sueli Maria Marino
author2_role author
author
author
dc.contributor.author.fl_str_mv Fernandes Junior, Roberto Cid
Dottori, Horacio Alberto
Gruenwald, Ruth B.
Viegas, Sueli Maria Marino
dc.subject.por.fl_str_mv Astrofisica extragalatica
Astronomia e astrofisica
Galaxias seyfert
Metalicidade
topic Astrofisica extragalatica
Astronomia e astrofisica
Galaxias seyfert
Metalicidade
description The aim of this paper is to study in detail the Terlevich & Melnick starburst-warmers scenario for type 2 Seyferts and LINERs, which postulates a young cluster containing stars with temperatures about 150 000 K as the heating source in these objects. A numerical code was developed to compute the total spectrum of a star cluster given its age and initial mass function. The ionizing spectra so obtained were used in the photoionization code AANGABA to calculate the nebular ernission-line spectra for a grid of cloud parameters covering different densities (and gradients), ionization parameters and metallicities. The evolution of the system was followed on classical diagnostic diagrams and a very good agreement with Terlevich & Melnick's results was found. We conclude that warmers can indeed be the ionizing source in many narrow-line AGN, although the coverage of AGN areas on diagnostic diagrams is not complete. We find the warmers model successful within a metallicity range between ~~0.5 and 2Z̛. The upper limit is set by the strong cloud cooling by forbidden lines. On the other hand, at Z<~0.5 Z̛ fewer stars would be thrown into 'warmer' phases due to the smaller mass-loss rates, and even if warmers occur the ernission-line spectrum would correspond to an H II galaxy rather than to an AGN. The chernical pollution of the gas by the strongly processed stellar winds of massive stars is also studied. Our results suggest that the nitrogen overabundance of AGN frequently claimed in the literature arises quite naturally in this scenario.
publishDate 1992
dc.date.issued.fl_str_mv 1992
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dc.relation.ispartof.pt_BR.fl_str_mv Monthly Notices of the Royal Astronomical Society. London. Vol. 255, no. 1 (Mar. 1992), p. 165-176
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