Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Clumpy photon-dominated regions in Carina. I. [CI] and mid-J CO lines in
  two 4'x4' fields   The Carina region is an excellent astrophysical laboratory for studying the
feedback mechanisms of newly born, very massive stars within their natal giant
molecular clouds (GMCs) at only 2.35 kpc distance. We use a clumpy PDR model to
analyse the observed intensities of atomic carbon and CO and to derive the
excitation conditions of the gas. The NANTEN2-4m submillimeter telescope was
used to map the [CI] 3P1-3P0, 3P2-3P1 and CO 4-3, 7-6 lines in two 4'x4'
regions of Carina where molecular material interfaces with radiation from the
massive star clusters. One region is the northern molecular cloud near the
compact OB cluster Tr14, and the second region is in the molecular cloud south
of etaCar and Tr16. These data were combined with 13CO SEST spectra, HIRES/IRAS
60um and 100um maps of the FIR continuum, and maps of 8um IRAC/Spitzer and MSX
emission. We used the HIRES far-infrared dust data to create a map of the FUV
field heating the gas. The northern region shows an FUV field of a few 1000 in
Draine units while the field of the southern region is about a factor 10
weaker. We constructed models consisting of an ensemble of small spherically
symmetric PDR clumps within the 38" beam (0.43pc), which follow canonical
power-law mass and mass-size distributions. We find that an average local clump
density of 2x10**5 cm-3 is needed to reproduce the observed line emission at
two selected interface positions. Stationary, clumpy PDR models reproduce the
observed cooling lines of atomic carbon and CO at two positions in the Carina
Nebula.

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The categories of this paper are: nlin
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The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
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The categories of this paper are: econ
34
The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: cond-mat
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The categories of this paper are: physics
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The categories of this paper are: chao-dyn
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The categories of this paper are: cs
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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an