Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Ages of Globular Clusters in NGC 4365 Revisited with Deep HST
  Observations   We present new Hubble Space Telescope (HST)-NIC3, near-infrared H-band
photometry of globular clusters (GC) around NGC 4365 and NGC 1399 in
combination with archival HST-WCPC2 and ACS optical data. We find that NGC 4365
has a number of globular clusters with bluer optical colors than expected for
their red optical to near-infrared colors and an old age. The only known way to
explain these colors is with a significant population of intermediate-age (2-8
Gyr) clusters in this elliptical galaxy. In contrast, NGC 1399 reveals no such
population. Our result for NGC 1399 is in agreement with previous spectroscopic
work that suggests that its clusters have a large metallicity spread and are
nearly all old. In the literature, there are various results from spectroscopic
studies of modest samples of NGC 4365 globular clusters. The spectroscopic data
allow for either the presence or absence of a significant population of
intermediate-age clusters, given the index uncertainties indicated by comparing
objects in common between these studies and the few spectroscopic candidates
with optical to near-IR colors indicative of intermediate ages. Our new near-IR
data of the NGC 4365 GC system with much higher signal-to-noise agrees well
with earlier published photometry and both give strong evidence of a
significant intermediate-age component. The agreement between the photometric
and spectroscopic results for NGC 1399 and other systems lends further
confidence to this conclusion, and to the effectiveness of the near-IR
technique.

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The categories of this paper are: cs
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ex
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The categories of this paper are: physics
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The categories of this paper are: econ
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol