Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Circumnuclear Star Clusters in the Galaxy Merger NGC 6240, Observed with
  Keck Adaptive Optics and HST   We discuss images of the central ~10 kpc (in projection) of the galaxy merger
NGC 6240 at H and K' bands, taken with the NIRC2 narrow camera on Keck II using
natural guide star adaptive optics. We detect 28 star clusters in the NIRC2
images, of which only 7 can be seen in the similar-spatial-resolution, archival
WFPC2 Planetary Camera data at either B or I bands. Combining the NIRC2 narrow
camera pointings with wider NICMOS NIC2 images taken with the F110W, F160W, and
F222M filters, we identify a total of 32 clusters that are detected in at least
one of these 5 infrared (lambda > 1 micron) bandpasses. By comparing to
instantaneous burst, stellar population synthesis models (Bruzual & Charlot
2003), we estimate that most of the clusters are consistent with being ~15 Myr
old and have photometric masses ranging from 7E5 M_sun to 4E7 M_sun. The total
contribution to the star formation rate (SFR) from these clusters is
approximately 10 M_sun/year, or ~10% of the total SFR in the nuclear region. We
use these newly discovered clusters to estimate the extinction toward NGC
6240's double nuclei, and find values of A_V as high as 14 magnitudes along
some sightlines, with an average extinction of A_V~7 mag toward sightlines
within ~3 arcsec of the double nuclei.

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The categories of this paper are: stat
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
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The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
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The categories of this paper are: funct-an
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph