Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for An Intermediate-Age, Metal-rich Population of Globular
  Clusters in NGC 4365   We present spectroscopy for globular clusters (GCs) in the elliptical galaxy
NGC 4365, obtained with the LRIS spectrograph on the Keck I telescope. Previous
studies have shown that the optical color distribution of GCs in NGC 4365 lacks
the bimodal structure that is common in globular cluster systems, showing only
a single broad peak. Measurements of Balmer line indices (Hbeta, Hgamma and
Hdelta) on the GC spectra support recent suggestions by Puzia et al., based on
optical and near-infrared photometry, that some of the clusters in NGC 4365 are
intermediate-age (2-5 Gyrs) and metal-rich (-0.4<[Z/H]<0) rather than old
(~10-15 Gyrs) and metal-poor. We also find some genuinely metal-poor, old
clusters, suggesting that the ages and metallicities of the two populations
conspire to produce the single broad distribution observed in optical colors.

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The categories of this paper are: adap-org
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The categories of this paper are: eess
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
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The categories of this paper are: supr-con
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph