Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exploring the Nucleus of the Gigamaser Galaxy TXS 2226-184   We present Very Long Baseline Array (VLBA) observations of the Gigamaser
galaxy TXS2226-184 at 1.3 and 5 GHz. These observations reveal the parsec-scale
radio structure of this Seyfert galaxy with exceptionally luminous water maser
emission. The source is found to be extended on scales of 10-100 pc with some
embedded compact sources, but has no readily identifiable flat-spectrum active
nucleus. This morphology resembles that of the nearby compact starburst galaxy
Mrk 273, although no significant FIR emission has been detected to support the
starburst scenario. The narrow (125 km/s) HI absorption in TXS2226-184
discovered with the VLA is also detected with the VLBA. This HI absorption is
distributed across the extended emission, probably co-spatial with the water
masers. The broad (420 km/s) line seen by the VLA is not detected, suggesting
that it arises from more extended gas which is absorbing the emission beyond
the central tens of parsecs.

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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: econ
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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-th