Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopic Diagnostics of the Mid-Infrared Features of the Dark
  Globule, DC 314.8-5.1, with the Spitzer Space Telescope   We present an analysis of the mid-infrared spectra, obtained from the Spitzer
Space Telescope, of the dark globule, DC 314.8--5.1, which is at the onset of
low-mass star formation. The target has a serendipitous association with a
B-type field star, which illuminates a reflection nebula in the cloud. We focus
on the polycyclic aromatic hydrocarbon (PAH) emission features prevalent
throughout the mid-infrared range. The analysis of the spectra with the PAHFIT
software as well as pypahdb package, shows that (i) the intensities of PAH
features decrease over distance from the ionizing star toward the cloud center,
some however showing a saturation at larger distances; (ii) the relative
intensities of the 6.2 and 8.6 features with respect to the 11.2 $\mu$m feature
remain high throughout the globule, suggesting a larger cation-to-neutral PAH
ratio than the one following from our estimate of the ionization parameter; the
breakdown from pypahdb confirms a high ionized fraction within the cloud; (iii)
the pypahdb results display a decrease in large PAH fraction with increased
distance from HD 130079, as well as a statistically significant correlation
between the large size fraction and the ionized fraction across the globule;
(iv) the 7.7 PAH feature displays a peak nearer to 7.8 $\mu$m suggesting a less
processed PAH population; (v) the H$_2$ S(0) line is detected at larger
distances from the ionizing star. All in all, our results suggest divergent
physical conditions within the quiescent cloud DC 314.8--5.1 as compared to
molecular clouds with ongoing starformation.

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The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an