The stellar content of active galaxies

We present the results of a long-slit spectroscopic study of 38 active and four normal galaxies. Stellar absorption features, continuum colours and their radial variations are analysed in an effort to characterize the stellar population in these galaxies and detect the presence of a featureless cont...

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Detalles Bibliográficos
Autores: Fernandes Junior, Roberto Cid, Storchi-Bergmann, Thaisa, Schmitt, Henrique Roberto
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:1998
País:Brasil
Institución:Universidade Federal do Rio Grande do Sul (UFRGS)
Repositorio:Repositório Institucional da UFRGS
Idioma:inglés
OAI Identifier:oai:www.lume.ufrgs.br:10183/88373
Acceso en línea:http://hdl.handle.net/10183/88373
Access Level:acceso abierto
Palabra clave:Galáxias
Nucleo galatico
Galaxias seyfert
Galaxies: active
Galaxies: general
Galaxies: nuclei
Galaxies: seyfert
Galaxies: stellar content
Descripción
Sumario:We present the results of a long-slit spectroscopic study of 38 active and four normal galaxies. Stellar absorption features, continuum colours and their radial variations are analysed in an effort to characterize the stellar population in these galaxies and detect the presence of a featureless continuum underlying the starlight spectral component. Spatial variations of the equivalent widths of conspicuous absorption lines and continuum colours are detected in most galaxies. Star-forming rings, in particular, leave clear fingerprints in the equivalent widths and colour profiles. We find that the stellar populations in the inner regions of active galaxies present a variety of characteristics, and cannot be represented by a single starlight template. Dilution of the stellar lines by an underlying featureless continuum is detected in most broadlined objects, but little or no dilution is found for most of the 20 type 2 Seyferts in the sample. Colour gradients are also ubiquitous. In particular, all but one of the observed Seyfert 2s are redder at the nucleus than in its immediate vicinity. Possible consequences of these findings are briefly outlined.