Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ionized Gas in the Smith Cloud   We present WHAM observations of Halpha, [N II], and [S II] in the Smith
Cloud. A map of Halpha emission from the cloud shows ionized gas coincident
with the brightest H I emission, but nearly-as-bright Halpha in some regions
with faint H I. The ionized mass of the cloud is at least as large as the
neutral mass, > 10^6 M_sun. Ionized gas in the core of the Smith Cloud has an
electron temperature 6000 K < T < 16000 K. The observed ratio [N II] / Halpha =
0.39 \pm 0.09 shows that the cloud has a non-primordial nitrogen abundance, 0.1
- 1 times solar.

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The categories of this paper are: cond-mat
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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: supr-con
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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph