LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES

We present spectrophotometry of 42 southern H II galaxies (H II Gs) recently discovered in the Calan-Tololo Spectroscopic Survey. Physical conditions and He, N, Ne and O abundances of the ionized regions of these galaxies were derived. We found that most of the objects have 7.9 less-than-or-equal-to...

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Detalles Bibliográficos
Autores: PENA, M, RUIZ, MT, MAZA, J
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:1991
País:México
Institución:Universidad Nacional Autónoma de México
Repositorio:Sistema de Información de la Facultad de Ciencias, UNAM
OAI Identifier:oai:repositorio.fciencias.unam.mx:11154/3574
Acceso en línea:http://hdl.handle.net/11154/3574
Access Level:acceso abierto
Palabra clave:Astronomy & Astrophysics
GALAXIES
H-II GALAXIES
INTERSTELLAR MEDIUM
ABUNDANCES
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spelling LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIESPENA, MRUIZ, MTMAZA, JAstronomy & AstrophysicsGALAXIESH-II GALAXIESINTERSTELLAR MEDIUMABUNDANCESWe present spectrophotometry of 42 southern H II galaxies (H II Gs) recently discovered in the Calan-Tololo Spectroscopic Survey. Physical conditions and He, N, Ne and O abundances of the ionized regions of these galaxies were derived. We found that most of the objects have 7.9 less-than-or-equal-to log O/H less-than-or-equal-to 8.3, that is, a factor between 10 and 4 lower than the solar value. The sample shows a tight correlation between Ne and O abundances that is well fitted by the linear regression log Ne/O = (1.18 +/- 0.07) log O/H - (2.21 +/- 0.54), with a mean value <log Ne/log O> = -0.70 +/- 0.08. For 10 H II Gs of the sample we found no correlation between N/O ratio and O abundance. The mean value of log N/O for these objects is - 1.41 +/- 0.10. Two other objects show a much larger N/O ratio. For a sample that includes the objects in this work and those reported by Campbell et al. (1986), we discuss the relation between some oxygen emission line intensity ratios and the physical conditions of the ionized region by comparing the observational data with the predictions of a grid of ionization structure models. An attempt is made to study the behavior of the effective temperature of the ionizing cluster and the ionization parameter for different metallicities. It is found that the mean T(eff) of the high O abundance H II Gs is lower than that in low abundance objects. We have estimated the ionization parameter for the regions in the sample and we derive a mean value of 0.005. From the H II Gs showing the highest ionization degree we deduced that, for a given O abundance, there is an upper limit, <U>max, for the ionization parameter. This upper limit increases smoothly with decreasing metallicity. In the range 7.8 less-than-or-equal-to log O/H less-than-or-equal-to 9.0, the behavior of <U>max is well represented by the expression: log <U>max = (-1.19 +/- 0.09)log O/H + (7.52 +/- 0.78).2011-01-22T10:28:41Z2011-01-22T10:28:41Z1991info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article0004-6361http://hdl.handle.net/11154/35743458251(2):417-430reponame:Sistema de Información de la Facultad de Ciencias, UNAMinstname:Universidad Nacional Autónoma de Méxicoinstacron:UNAMenAstronomy and Astrophysicsinfo:eu-repo/semantics/openAccessoai:repositorio.fciencias.unam.mx:11154/35742025-09-17T19:21:50Z
dc.title.none.fl_str_mv LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES
title LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES
spellingShingle LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES
PENA, M
Astronomy & Astrophysics
GALAXIES
H-II GALAXIES
INTERSTELLAR MEDIUM
ABUNDANCES
title_short LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES
title_full LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES
title_fullStr LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES
title_full_unstemmed LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES
title_sort LINE ANALYSIS AND NEBULAR ABUNDANCES IN H-II GALAXIES
dc.creator.none.fl_str_mv PENA, M
RUIZ, MT
MAZA, J
author PENA, M
author_facet PENA, M
RUIZ, MT
MAZA, J
author_role author
author2 RUIZ, MT
MAZA, J
author2_role author
author
dc.subject.none.fl_str_mv Astronomy & Astrophysics
GALAXIES
H-II GALAXIES
INTERSTELLAR MEDIUM
ABUNDANCES
topic Astronomy & Astrophysics
GALAXIES
H-II GALAXIES
INTERSTELLAR MEDIUM
ABUNDANCES
description We present spectrophotometry of 42 southern H II galaxies (H II Gs) recently discovered in the Calan-Tololo Spectroscopic Survey. Physical conditions and He, N, Ne and O abundances of the ionized regions of these galaxies were derived. We found that most of the objects have 7.9 less-than-or-equal-to log O/H less-than-or-equal-to 8.3, that is, a factor between 10 and 4 lower than the solar value. The sample shows a tight correlation between Ne and O abundances that is well fitted by the linear regression log Ne/O = (1.18 +/- 0.07) log O/H - (2.21 +/- 0.54), with a mean value <log Ne/log O> = -0.70 +/- 0.08. For 10 H II Gs of the sample we found no correlation between N/O ratio and O abundance. The mean value of log N/O for these objects is - 1.41 +/- 0.10. Two other objects show a much larger N/O ratio. For a sample that includes the objects in this work and those reported by Campbell et al. (1986), we discuss the relation between some oxygen emission line intensity ratios and the physical conditions of the ionized region by comparing the observational data with the predictions of a grid of ionization structure models. An attempt is made to study the behavior of the effective temperature of the ionizing cluster and the ionization parameter for different metallicities. It is found that the mean T(eff) of the high O abundance H II Gs is lower than that in low abundance objects. We have estimated the ionization parameter for the regions in the sample and we derive a mean value of 0.005. From the H II Gs showing the highest ionization degree we deduced that, for a given O abundance, there is an upper limit, <U>max, for the ionization parameter. This upper limit increases smoothly with decreasing metallicity. In the range 7.8 less-than-or-equal-to log O/H less-than-or-equal-to 9.0, the behavior of <U>max is well represented by the expression: log <U>max = (-1.19 +/- 0.09)log O/H + (7.52 +/- 0.78).
publishDate 1991
dc.date.none.fl_str_mv 1991
2011-01-22T10:28:41Z
2011-01-22T10:28:41Z
dc.type.none.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv 0004-6361
http://hdl.handle.net/11154/3574
3458
identifier_str_mv 0004-6361
3458
url http://hdl.handle.net/11154/3574
dc.language.none.fl_str_mv en
language_invalid_str_mv en
dc.relation.none.fl_str_mv Astronomy and Astrophysics
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.source.none.fl_str_mv 251(2):417-430
reponame:Sistema de Información de la Facultad de Ciencias, UNAM
instname:Universidad Nacional Autónoma de México
instacron:UNAM
instname_str Universidad Nacional Autónoma de México
instacron_str UNAM
institution UNAM
reponame_str Sistema de Información de la Facultad de Ciencias, UNAM
collection Sistema de Información de la Facultad de Ciencias, UNAM
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.812429

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