Repositório Digital

A- A A+

Population synthesis in galactic nuclei using a library of star cluster

.

Population synthesis in galactic nuclei using a library of star cluster

Mostrar registro completo

Estatísticas

Título Population synthesis in galactic nuclei using a library of star cluster
Autor Bica, Eduardo Luiz Damiani
Abstract Population syntheses for normal nuclei in E/SO and spiral galaxies are derived using a library of star clusters. This method allows to determine the chemical enrichment and to date successive generations of star formation. Thus it is more than a simple population synthesis, providing for the first time a direct estima te of the chemical evolution in these nuclei. For the E/SO groups following the normal metallicity vs luminosity relationship, the last generation of stars in the nucleus has reached a metallicity 4 times solar for Mв = -22 and 0.5 to 0.3 solar for Mв = -18. The bulk o f the population is older than 1O Gyr but these galaxies have formed stars at least until look-back times of ̃ 5 Gyr. Some metallicity dispersion is detected within the nuclei: in the most metal rich group, around 10% of the optical flux arises from populations with metallicities lower than solar. For the relatively less numerous bluer E/SO groups, younger age components are present, which we have been able to isola te and date. The red spiral groups also form a metallicity sequence which is related to the bulge luminosity, spanning metallicities from a factor4 solar to solar. Finally, the groups of bluer spiral nuclei contain younger age components superimposed on an older population, which has reached at least the solar metallicity. The relative importance of the star formation bursts with respect to the older population is derived: in the bluest group, with NGC 5236 as a prototype, the population younger than 3 10⁸ yr amounts to 87% of the flux at 4000 Å and 57% at 9000 Å. The present method constitutes a powerful tool for the interpretation of composite spectra and will certainly have many applications in the study of large redshift galaxies.
Contido em Astronomy and astrophysics. Vol. 195, no. 1/2 (Apr. 1988), p. 76-92
Assunto Astrofisica
Evolucao galatica
Nucleo galatico
[en] Galaxies: evolution of
[en] Galaxies: general
[en] Galaxies: nuclei of
[en] Galaxies: stellar content of
Origem Estrangeiro
Tipo Artigo de periódico
URI http://hdl.handle.net/10183/98031
Arquivos Descrição Formato
000014827.pdf (635.0Kb) 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.