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Título:
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Evidence for intermediate-age stellar populations in early-type galaxies from K-band spectroscopy
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Autores:
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Mármol Queraltó, E. ;
Cardiel López, Nicolás ;
Sánchez Blázquez, P. ;
Trager, S. C. ;
Peletier, R. F. ;
Kuntschner, H. ;
Silva, D. R. ;
Cenarro, A. J. ;
Vazdekis, A. ;
Gorgas García, Francisco Javier
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Tipo de documento:
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texto impreso
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Editorial:
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IOP publishing ltd, 2009-11-10
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Dimensiones:
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application/pdf
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Nota general:
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info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Física: Astrofísica
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Materia = Ciencias: Física: Astronomía
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Materia = Ciencias: Física: Física atmosférica
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Tipo = Artículo
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Resumen:
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The study of stellar populations in early-type galaxies in different environments is a powerful tool for constraining their star formation histories. This study has been traditionally restricted to the optical range, where dwarfs around the turn-off and stars at the base of the red giant branch dominate the integrated light at all ages. The near-infrared spectral range is especially interesting since in the presence of an intermediate-age population, asymptotic giant branch stars are the main contributors. In this Letter, we measure the near-infrared indices Na I and D(CO) for a sample of 12 early-type galaxies in low-density environments and compare them with the Fornax galaxy sample presented by Silva et al.. The analysis of these indices in combination with Lick/IDS indices in the optical range reveals that (1) the Na I index is a metallicity indicator as good as C4668 in the optical range, and (2) D(CO) is a tracer of intermediate-age stellar populations. We find that low-mass galaxies in low-density environments show higher Na I and D(CO) than those located in the Fornax cluster, which points toward a late stage of star formation for the galaxies in less dense environments, in agreement with results from other studies using independent methods.
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En línea:
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https://eprints.ucm.es/id/eprint/28023/1/cardiel22libre.pdf
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