Mostrar registro simples

dc.contributor.authorStorchi-Bergmann, Thaisapt_BR
dc.contributor.authorSchmitt, Henrique Robertopt_BR
dc.contributor.authorCalzetti, Danielapt_BR
dc.contributor.authorKinney, Anne Louisept_BR
dc.date.accessioned2014-12-04T02:13:48Zpt_BR
dc.date.issued1998pt_BR
dc.identifier.issn0004-6256pt_BR
dc.identifier.urihttp://hdl.handle.net/10183/107739pt_BR
dc.description.abstractWe investigate two chemical abundance calibrations for the narrow-line region (NLR) of active galaxies in terms of three easily observable optical emission-line ratios, namely, [O III] λλ4959, 5007/Hβ; [N II] λλ6548, 6584/Hα; and [O II] λ3727/[O III] λλ4959, 5007. The calibrations are obtained from a grid of models on the assumption that the main process responsible for the production of these lines is photoionization by a "typical" active galactic nucleus continuum. The elemental abundances vary with oxygen, except nitrogen, which is assumed to be a product of secondary nucleosynthesis. The calibrations are calculated for the range 8.4≤12]log (O/H)≤9.4 and tested using NLR data for a sample of Seyfert galaxies and LINERs that have H II regions in the vicinity of the nucleus. The gaseous abundances of these H II regions have been determined in previous works, and the NLR abundances are obtained on the assumption that they can be extrapolated from those of the H II regions. The calibrations work very well for the Seyfert galaxies, yielding abundance values that agree with those obtained from the H II regions, and can thus be used for quick estimates of the chemical abundances of the NLRs. For the LINERs, the calibrations yield lower values than those derived from the corresponding H II regions, suggesting that the assumptions of the models do not apply for them and that there are di†erent physical processes at work in the NLR of the LINERs.en
dc.format.mimetypeapplication/pdf
dc.language.isoengpt_BR
dc.relation.ispartofThe Astronomical journal. New York. Vol. 115, no. 3 (Mar. 1998), p. 909-914pt_BR
dc.rightsOpen Accessen
dc.subjectGalaxies : activeen
dc.subjectAstrofisica extragalaticapt_BR
dc.subjectGalaxies : ISMen
dc.subjectNucleo galaticopt_BR
dc.subjectAbundanciapt_BR
dc.subjectGalaxies : nucleien
dc.subjectGasespt_BR
dc.subjectGalaxies : Seyferten
dc.subjectDinâmicapt_BR
dc.subjectGalaxias seyfertpt_BR
dc.subjectRegiões HIIpt_BR
dc.titleChemical abundance calibrations for the narrow-line region of active galaxiespt_BR
dc.typeArtigo de periódicopt_BR
dc.identifier.nrb000210688pt_BR
dc.type.originEstrangeiropt_BR


Thumbnail
   

Este item está licenciado na Creative Commons License

Mostrar registro simples