Repositório Digital

A- A A+

Dust extinction of the stellar continua in Starburst galaxies : the ultraviolet and optical extinction law

.

Dust extinction of the stellar continua in Starburst galaxies : the ultraviolet and optical extinction law

Mostrar registro completo

Estatísticas

Título Dust extinction of the stellar continua in Starburst galaxies : the ultraviolet and optical extinction law
Autor Calzetti, Daniela
Kinney, Anne Louise
Storchi-Bergmann, Thaisa
Abstract We analyze the IUE UV and the optical spectra of 39 starburst and blue compact galaxies in order to study the average properties of dust extinction in extended regions of galaxies. The optical spectra have been obtained using an aperture which matches that of lUE, so comparable regions within each galaxy are sampled. The data from the 39 galaxies are compared with five models for the geometrical distribution of dust, adopting as extinction laws both the Milky Way and the Large Magellanic Cloud Jaws. The commonly used uniform dust screen is included among the models. We find that none of the five models is in satisfactory agreement with the data. In order to understand the discrepancy between the data and the models, we have derived an extinction law directly from the data in the UV and optical wavelength range. The resulting curve is characterized by an overall slope which is more gray than the Milky Way extinction Jaw's slope, and by the absence of the 2175 Å dust feature. Remarkably, the difference in optical depth between the Balmer emission lines Hα and Hβ is about a factor of 2 larger than the difference in the optical depth between the continuum underlying the two Balmer lines. We interpret this discrepancy as a consequence of the fact that the hot ionizing stars are associated with dustier regions than the cold stellar population is. The absence of the 2175 Å dust feature can be due either to the effects of the scattering and clumpiness of the dust or to a chemical composition different from that of the Milky Way dust grains. Disentangling the two interpretations is not easy because of the complexity of the spatial distribution of the emitting regions. The extinction law of UV and optical spectral continua of extended regions can be applied to the spectra of medium- and high-redshift galaxies, where extended regions of a galaxy are, by necessity, sampled.
Contido em The astrophysical journal. Chicago. Vol. 429, no. 2, pt. 1 (July 1994), p. 582-601
Assunto Astrofisica extragalatica
Espectros astronômicos
Explosoes de estrelas
Galaxias
Gases ionizados
Materia interestelar
Metalicidade
Observações astronômicas no visível
Poeira cosmica
Populacoes estelares
Via láctea
[en] Dust, extinction
[en] Galaxies: ISM
[en] Galaxies: photometry
[en] Galaxies: starburst
[en] Ultraviolet: galaxies
Origem Estrangeiro
Tipo Artigo de periódico
URI http://hdl.handle.net/10183/108843
Arquivos Descrição Formato
000254247.pdf (441.3Kb) 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.