Evidence for a precessing accretion disk in the nucleus of NGC 1097
Autor(a) principal: | |
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Data de Publicação: | 1997 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/108774 |
Resumo: | We present new spectroscopic observations of the LINER (and now Seyfert 1) nucleus of NGC 1097, and discuss the evolution of its broad, double-peaked Balmer lines. When originally discovered in 1991, the red peak of the double-peaked Hα line was stronger than the blue, while by 1994 the Ha profile had become almost symmetric and the integrated line flux had decreased to half its original value. Our new spectrum, taken in 1996, shows that the broad, double-peaked lines have returned to almost their original strengths, the profiles of Hβ and Hα are identical to within errors, and the broad-line emitting region is unreddened. However, the proÐle of the Balmer lines is now such that the blue peak is stronger than the red, opposite to the asymmetry observed in 1991. Various models are considered for the observed behavior, all assuming that the emission lines originate in an accretion disk. We present a refined version of the precessing, planar, elliptical accretion-ring model proposed by Storchi-Bergmann et al. and Eracleous et al. This model provides an acceptable fit to the line profiles. We also consider the possibility that the line-profile evolution results from a precessing warp in the disk, induced by irradiation from the center, and show that the range of radii and precession timescales expected in this model are consistent with the observations. The sudden appearance of the “disklike" broad-line profiles in NGC 1097 could have resulted from the formation of a new accretion disk due, for example, to the tidal disruption of a star or the illumination of a preexisting disk by a transient ionizing source at the center of the disk. |
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Storchi-Bergmann, ThaisaEracleous, MichaelRuiz, Maria TeresaLivio, MarioWilson, Andrew S.Filippenko, Alexei V.2015-01-07T02:10:39Z19970004-637Xhttp://hdl.handle.net/10183/108774000198078We present new spectroscopic observations of the LINER (and now Seyfert 1) nucleus of NGC 1097, and discuss the evolution of its broad, double-peaked Balmer lines. When originally discovered in 1991, the red peak of the double-peaked Hα line was stronger than the blue, while by 1994 the Ha profile had become almost symmetric and the integrated line flux had decreased to half its original value. Our new spectrum, taken in 1996, shows that the broad, double-peaked lines have returned to almost their original strengths, the profiles of Hβ and Hα are identical to within errors, and the broad-line emitting region is unreddened. However, the proÐle of the Balmer lines is now such that the blue peak is stronger than the red, opposite to the asymmetry observed in 1991. Various models are considered for the observed behavior, all assuming that the emission lines originate in an accretion disk. We present a refined version of the precessing, planar, elliptical accretion-ring model proposed by Storchi-Bergmann et al. and Eracleous et al. This model provides an acceptable fit to the line profiles. We also consider the possibility that the line-profile evolution results from a precessing warp in the disk, induced by irradiation from the center, and show that the range of radii and precession timescales expected in this model are consistent with the observations. The sudden appearance of the “disklike" broad-line profiles in NGC 1097 could have resulted from the formation of a new accretion disk due, for example, to the tidal disruption of a star or the illumination of a preexisting disk by a transient ionizing source at the center of the disk.application/pdfengThe astrophysical journal. Chicago. Vol. 489, no. 1, pt. 1 (Nov. 1997), p. 87-93Discos de acrecaoEspectros astronômicosGaláxia NGC 1097Galaxias seyfertNucleo galaticoAccretion, accretion disksGalaxies : individual (NGC 1097)Galaxies : nucleiGalaxies : seyfertLine : profilesEvidence for a precessing accretion disk in the nucleus of NGC 1097Estrangeiroinfo: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:UFRGSORIGINAL000198078.pdf000198078.pdfTexto completo (inglês)application/pdf304269http://www.lume.ufrgs.br/bitstream/10183/108774/1/000198078.pdff156771e62ca6e0927c692c3cef6023cMD51TEXT000198078.pdf.txt000198078.pdf.txtExtracted Texttext/plain34310http://www.lume.ufrgs.br/bitstream/10183/108774/2/000198078.pdf.txte659467f4ad59918c430dbdd83a93c2cMD52THUMBNAIL000198078.pdf.jpg000198078.pdf.jpgGenerated Thumbnailimage/jpeg2324http://www.lume.ufrgs.br/bitstream/10183/108774/3/000198078.pdf.jpg6acd60d5a2f29481b1ba9307867629f9MD5310183/1087742018-10-23 08:34:55.748oai:www.lume.ufrgs.br:10183/108774Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2018-10-23T11:34:55Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Evidence for a precessing accretion disk in the nucleus of NGC 1097 |
title |
Evidence for a precessing accretion disk in the nucleus of NGC 1097 |
spellingShingle |
Evidence for a precessing accretion disk in the nucleus of NGC 1097 Storchi-Bergmann, Thaisa Discos de acrecao Espectros astronômicos Galáxia NGC 1097 Galaxias seyfert Nucleo galatico Accretion, accretion disks Galaxies : individual (NGC 1097) Galaxies : nuclei Galaxies : seyfert Line : profiles |
title_short |
Evidence for a precessing accretion disk in the nucleus of NGC 1097 |
title_full |
Evidence for a precessing accretion disk in the nucleus of NGC 1097 |
title_fullStr |
Evidence for a precessing accretion disk in the nucleus of NGC 1097 |
title_full_unstemmed |
Evidence for a precessing accretion disk in the nucleus of NGC 1097 |
title_sort |
Evidence for a precessing accretion disk in the nucleus of NGC 1097 |
author |
Storchi-Bergmann, Thaisa |
author_facet |
Storchi-Bergmann, Thaisa Eracleous, Michael Ruiz, Maria Teresa Livio, Mario Wilson, Andrew S. Filippenko, Alexei V. |
author_role |
author |
author2 |
Eracleous, Michael Ruiz, Maria Teresa Livio, Mario Wilson, Andrew S. Filippenko, Alexei V. |
author2_role |
author author author author author |
dc.contributor.author.fl_str_mv |
Storchi-Bergmann, Thaisa Eracleous, Michael Ruiz, Maria Teresa Livio, Mario Wilson, Andrew S. Filippenko, Alexei V. |
dc.subject.por.fl_str_mv |
Discos de acrecao Espectros astronômicos Galáxia NGC 1097 Galaxias seyfert Nucleo galatico |
topic |
Discos de acrecao Espectros astronômicos Galáxia NGC 1097 Galaxias seyfert Nucleo galatico Accretion, accretion disks Galaxies : individual (NGC 1097) Galaxies : nuclei Galaxies : seyfert Line : profiles |
dc.subject.eng.fl_str_mv |
Accretion, accretion disks Galaxies : individual (NGC 1097) Galaxies : nuclei Galaxies : seyfert Line : profiles |
description |
We present new spectroscopic observations of the LINER (and now Seyfert 1) nucleus of NGC 1097, and discuss the evolution of its broad, double-peaked Balmer lines. When originally discovered in 1991, the red peak of the double-peaked Hα line was stronger than the blue, while by 1994 the Ha profile had become almost symmetric and the integrated line flux had decreased to half its original value. Our new spectrum, taken in 1996, shows that the broad, double-peaked lines have returned to almost their original strengths, the profiles of Hβ and Hα are identical to within errors, and the broad-line emitting region is unreddened. However, the proÐle of the Balmer lines is now such that the blue peak is stronger than the red, opposite to the asymmetry observed in 1991. Various models are considered for the observed behavior, all assuming that the emission lines originate in an accretion disk. We present a refined version of the precessing, planar, elliptical accretion-ring model proposed by Storchi-Bergmann et al. and Eracleous et al. This model provides an acceptable fit to the line profiles. We also consider the possibility that the line-profile evolution results from a precessing warp in the disk, induced by irradiation from the center, and show that the range of radii and precession timescales expected in this model are consistent with the observations. The sudden appearance of the “disklike" broad-line profiles in NGC 1097 could have resulted from the formation of a new accretion disk due, for example, to the tidal disruption of a star or the illumination of a preexisting disk by a transient ionizing source at the center of the disk. |
publishDate |
1997 |
dc.date.issued.fl_str_mv |
1997 |
dc.date.accessioned.fl_str_mv |
2015-01-07T02:10:39Z |
dc.type.driver.fl_str_mv |
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format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/108774 |
dc.identifier.issn.pt_BR.fl_str_mv |
0004-637X |
dc.identifier.nrb.pt_BR.fl_str_mv |
000198078 |
identifier_str_mv |
0004-637X 000198078 |
url |
http://hdl.handle.net/10183/108774 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
The astrophysical journal. Chicago. Vol. 489, no. 1, pt. 1 (Nov. 1997), p. 87-93 |
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info:eu-repo/semantics/openAccess |
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openAccess |
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