Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Far-IR Excited OH Lines from Orion KL Outflows   As part of the first far-IR line survey towards Orion KL, we present the
detection of seven new rotationally excited OH Lambda-doublets (at 48, 65, 71,
79, 98 and 115 um). Observations were performed with the Long Wavelength
Spectrometer (LWS) Fabry-Perots on board the Infrared Space Observatory (ISO).
In total, more than 20 resolved OH rotational lines, with upper energy levels
up to 620 K, have been detected at an angular and velocity resolutions of 80$''
and 33 km s^-1 respectively. OH line profiles show a complex behavior evolving
from pure absorption, P-Cygni type to pure emission. We also present a large
scale 6' declination raster in the OH ^2\Pi_3/2 J=5/2^+-3/2^- and ^2\Pi_3/2
J=7/2^-5/2^+ lines (at 119.441 and 84.597 um) revealing the decrease of
excitation outside the core of the cloud. From the observed profiles, mean
intrinsic line widths and velocity offsets between emission and absorption line
peaks we conclude that most of the excited OH arises from Orion outflow(s),
i.e. the ``plateau'' component. We determine an averaged OH abundance relative
to H_2 of X(OH)=(0.5-1.0)x10^-6, a kinetic temperature of 100 K and a density
of n(H_2)=5x10^5 cm^-3. Even with these conditions, the OH excitation is
heavily coupled with the strong dust continuum emission from the inner hot core
regions and from the expanding flow itself.

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The categories of this paper are: econ
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The categories of this paper are: math
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The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: cs
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-ph