Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of Extended Hot Water in the Outflow from NGC 2071   We report the results of spectroscopic mapping observations carried out
toward a ~1 min x 1 min region within the northern lobe of the outflow from NGC
2071 using the Infrared Spectrograph (IRS) of the Spitzer Space Telescope.
These observations covered the 5.2-37 um spectral region and have led to the
detection of a number of ionic, atomic, and molecular lines, including
fine-structure emission of Si+, Fe+, S++, S, the S(0)-S(7) pure rotational
lines of H2, the R(3) and R(4) transitions of HD, and at least 11 transitions
of H2O. In addition, the 6.2, 7.4, 7.6, 7.9, 8.6 and 11.3 um PAH emission bands
were also observed and several transitions of OH were tentatively detected.
Most of the detected line transitions were strong enough to map including, for
the first time, three transitions of hot H2O. We find that: (1) the water
emission is extended; (2) the extended emission is aligned with the outflow;
and, (3) the spatial distribution of the water emission generally follows that
observed for H2. Based on the measured line intensities, we derive an HD
abundance relative to H2 of 1.1-1.8 10^-5 and an H2O number density of 12-2
cm^3. The H2 density in the water-emitting region is not well constrained by
our observations, but is likely between 3 10^4 and 10^6 cm^3, yielding an H2O
abundance relative to H2 of between 2 10^-5 and 6 10^-4. Future observations
planned for the Herschel Space Observatory should greatly improve the density
estimate, and thus our knowledge of the H2O abundance, for the water-emitting
regions reported here. Finally, we note a possible departure from the H2O
ortho-to-para ratio of 3:1 expected for water formed in hot post-shocked gas,
suggesting that a significant fraction of the water vapor we detect may arise
from H2O sputtered from cold dust grains.

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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: math
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The categories of this paper are: physics
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: dg-ga