Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Si-bearing molecules towards IRC+10216: ALMA unveils the molecular
  envelope of CWLeo   We report the detection during the ALMA Cycle 0 of SiS rotational lines in
high-vibrational states as well as SiO and SiC$_2$ lines in their ground
vibrational state, towards IRC+10216. The spatial distribution of these
molecules shows compact emission for SiS and a more extended emission for SiO
and SiC$_2$, and also proves the existence of an increase in the SiC$_2$
emission at the outer shells of the circumstellar envelope. We analyze the
excitation conditions of the vibrationally excited SiS using the population
diagram technique and we used a large velocity gradient model to compare with
the observations. We found moderate discrepancies between the observations and
the models that could be explained if SiS lines detected are optically thick.
Additionally, the line profiles of the detected rotational lines in the high
energy vibrational states show a decreasing linewidth with increasing energy
levels. This may evidence that these lines could be excited only in the inner
shells, i.e. the densest and hottest, of the circumstellar envelope of
IRC+10216.

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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph
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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: econ
0
The categories of this paper are: hep-ph