A new stellar library in the region of the CO index at 2.3 μm. New index definition and empirical fitting functions

Mármol-Queraltó, E.; Cardiel, N.; Cenarro, A. J.; Vazdekis, A.; Gorgas, J.; Pedraz, S.; Peletier, R. F.; Sánchez-Blázquez, P.
Bibliographical reference

Astronomy and Astrophysics, Volume 489, Issue 2, 2008, pp.885-909

Advertised on:
10
2008
Number of authors
8
IAC number of authors
2
Citations
47
Refereed citations
41
Description
Context: The analysis of unresolved stellar populations demands evolutionary synthesis models with realistic physical ingredients and extended wavelength coverage. Aims: We quantitatively describe the first CO bandhead at 2.3 μm to allow stellar population models to provide improved predictions in this wavelength range. Methods: We observed a new stellar library with a better coverage of the stellar atmospheric parameter space than in earlier works. We performed a detailed analysis of the robustness of previous CO index definitions with spectral resolution, wavelength calibration, signal-to-noise ratio, and flux calibration. Results: We define a new line-strength index for the first CO bandhead at 2.3 μm, D_CO, better suited for stellar population studies than previous index definitions. We derive empirical fitting functions for the CO feature as a function of the stellar parameters (T_eff, log g and [Fe/H]), showing a detailed quantitative metallicity dependence.
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Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
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