2010A&A...510A..19L -
Astronomy and Astrophysics, volume 510, A19-19 (2010/2-1)
Integrated K-band spectra of old and intermediate-age globular clusters in the Large Magellanic Cloud.
LYUBENOVA M., KUNTSCHNER H., REJKUBA M., SILVA D.R., KISSLER-PATIG M., TACCONI-GARMAN L.E. and LARSEN S.S.
Abstract (from CDS):
Current stellar population models have arguably the largest uncertainties in the near-IR wavelength range, partly due to a lack of large and well calibrated empirical spectral libraries. In this paper we present a project whose aim it is to provide the first library of luminosity weighted integrated near-IR spectra of globular clusters to be used to test the current stellar population models and serve as calibrators for future ones. Our pilot study presents spatially integrated K-band spectra of three old (≥10Gyr) and metal poor ([Fe/H]~-1.4), and three intermediate age (1-2Gyr) and more metal rich ([Fe/H]~-0.4) globular clusters in the LMC. We measured the line strengths of the NaI, CaI and
12CO(2-0) absorption features. The NaI index decreases with increasing age and decreasing metallicity of the clusters. The D
CO index, used to measure the
12CO(2-0) line strength, is significantly reduced by the presence of carbon-rich TP-AGB stars in the globular clusters with age ∼1Gyr. This is in contradiction to the predictions of the stellar population models of Maraston (
2005MNRAS.362..799M). We find that this disagreement is due to the different CO absorption strength of carbon-rich Milky Way TP-AGB stars used in the models and the LMC carbon stars in our sample. For globular clusters with age ≥2Gyr we find D
CO index measurements consistent with the model predictions.
Abstract Copyright:
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Journal keyword(s):
Magellanic Clouds - stars: carbon - galaxies: star clusters
VizieR on-line data:
<Available at CDS (J/A+A/510/A19): clusters.dat sp/*>
Simbad objects:
59
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