Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ALMA view of the $\rho$ Ophiuchi A PDR with a 360-au beam: the [CI]
  emission originates from the plane-parallel PDR and extended gas   We present the results of data analysis of the [CI] ($^{3}P_{1}$-$^{3}P_{0}$)
emission from the $\rho$ Ophiuchi A photon-dominated region (PDR) obtained in
the ALMA ACA stand-alone mode with a spatial resolution of 2.''6 (360 au). The
[CI] emission shows filamentary structures with a width of $\sim$1000 au, which
are adjacent to the shell structure seen in the 4.5 $\mu$m map. We found that
the 4.5 $\mu$m emission, C$^0$, and CO are distributed in this order from the
excitation star (S1) in a complementary pattern. These results indicate that
[CI] is emitted from a thin layer in the PDR generated by the excitation star,
as predicted in the plane-parallel PDR model. In addition, extended [CI]
emission was also detected, which shows nearly uniform integrated intensity
over the entire field-of-view (1.'6$\times$1.'6). The line profile of the
extended component is different from that of the above shell component. The
column density ratio of C$^0$ to CO in the extended component was $\sim$2,
which is significantly higher than those of Galactic massive star-forming
regions (0.1-0.2). These results suggest that [CI] is emitted also from the
extended gas with a density of $n_\mathrm{H_2} \sim 10^3$ cm$^{-3}$, which is
not greatly affected by the excitation star.

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The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: stat
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin
9
The categories of this paper are: nlin
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas