Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Shock-enhanced ammonia emission in the Egg nebula   We present high angular resolution observations of the NH$_3$(1,1), (2,2) and
(3,3) inversion transitions from the Egg Nebula, the archetypical
proto-planetary nebula. The spatial distribution and kinematics of the emission
in all three lines show four distinct components or lobes that are aligned with
the polar and equatorial directions. The kinematics of the NH$_3$ emission is
also found to follow a clear pattern: redshifted emission in the South and West
and blueshifted emission in the North and East. The morphology and spatial
kinematics of NH$_3$ emission are shown to have strong similarity to that
observed previously in molecular hydrogen emission and CO emission which arise
from the shocked molecular gas. We also find that the higher lying inversion
transition NH$_3$ (2,2) and (3,3) are stronger in the polar direction in
comparison to the lower transition NH$_3$ (1,1). We conclude that the NH$_3$
emission traces the warm molecular gas, which is shocked and heated by the
interaction between the high velocity outflows and the surrounding envelope.
The presence of strong ammonia emission associated with the shock fronts and
the lack of the emission at the center of the nebula indicate that the
abundance of ammonia is significantly enhanced by shocks, a situation very
similar to that found in outflows from protostars.

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The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
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: dg-ga
1
The categories of this paper are: cs
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: math
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph