Repositório Digital

A- A A+

Chemical abundance calibrations for the narrow-line region of active galaxies

.

Chemical abundance calibrations for the narrow-line region of active galaxies

Mostrar registro completo

Estatísticas

Título Chemical abundance calibrations for the narrow-line region of active galaxies
Autor Storchi-Bergmann, Thaisa
Schmitt, Henrique Roberto
Calzetti, Daniela
Kinney, Anne Louise
Abstract We 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.
Contido em The Astronomical journal. New York. Vol. 115, no. 3 (Mar. 1998), p. 909-914
Assunto Abundancia
Astrofisica extragalatica
Dinamica
Galaxias seyfert
Gases
Nucleo galatico
Regiões HII
[en] Galaxies : active
[en] Galaxies : ISM
[en] Galaxies : nuclei
[en] Galaxies : Seyfert
Origem Estrangeiro
Tipo Artigo de periódico
URI http://hdl.handle.net/10183/107739
Arquivos Descrição Formato
000210688.pdf (166.3Kb) Texto completo (inglês) Adobe PDF Visualizar/abrir

Este item está licenciado na Creative Commons License

Este item aparece na(s) seguinte(s) coleção(ões)


Mostrar registro completo

Percorrer



  • O autor é titular dos direitos autorais dos documentos disponíveis neste repositório e é vedada, nos termos da lei, a comercialização de qualquer espécie sem sua autorização prévia.
    Projeto gráfico elaborado pelo Caixola - Clube de Criação Fabico/UFRGS Powered by DSpace software, Version 1.8.1.