Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: H$_2$O maser emission associated with the planetary nebula IRAS
  16333$-$4807   We present simultaneous observations of H$_2$O maser emission and radio
continuum at 1.3 cm carried out with the Australia Telescope Compact Array
towards two sources, IRAS 16333$-$4807 and IRAS 12405$-$6219, catalogued as
planetary nebula (PN) candidates, and where single-dish detections of H$_2$O
masers have been previously reported. Our goal was to unambiguously confirm the
spatial association of the H$_2$O masers with these two PN candidates. We
detected and mapped H$_2$O maser emission in both fields, but only in IRAS
16333$-$4807 the maser emission is spatially associated with the radio
continuum emission. The properties of IRAS 16333$-$4807 provide strong support
for the PN nature of the object, hereby confirming it as the fifth known case
of a H$_2$O maser-emitting PN. This source is bipolar, like the other four
known H$_2$O maser-emitting PNe, indicating that these sources might pertain to
a usual, but short phase in the evolution of bipolar PNe. In IRAS 12405$-$6219,
the H$_2$O maser and radio continuum emission are not associated with each
other and, in addition, the available data indicate that this source is an H II
region rather than a PN.

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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: math