Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A new stellar library in the region of the CO index at 2.3 $\mu$m. New
  index definition and empirical fitting functions   Context: The analysis of unresolved stellar populations demands evolutionary
synthesis models with realistic physical ingredients and extended wavelength
coverage.
  Aims: To obtain a quantitative description of the first CO bandhead at 2.3
$\mu$m, to allow stellar population models to provide improved predictions in
this wavelength range.
  Methods: We have observed a new stellar library with a better coverage of the
stellar atmospheric parameter space than preceding works. We have 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
$\mu$m, D$_{\rm CO}$, better suited for stellar population studies than
previous index definitions. We compute empirical fitting functions for the CO
feature as a function of the stellar parameters (T$_{\rm eff}$, $\log g$ and
[Fe/H]), showing a detailed quantitative metallicity dependence.

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The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph