Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: DDO 161 and UGCA 319: an isolated pair of nearby dwarf galaxies   We report HST/ACS observations of two nearby gas-rich dwarf galaxies: DDO 161
and UGCA 319. Their distances determined via the Tip of the Red Giant Branch
are 6.03 (-0.21/+0.29) Mpc and 5.75+-0.18 Mpc, respectively. The galaxies form
an isolated pair dynamically well separated from the nearest neighbors: KK 176
(7.28+-0.29 Mpc) and NGC 5068 (5.16+-0.21 Mpc). All four galaxies have a bulk
spatial peculiar velocity towards the Virgo cluster of ~158+-17 km/s in the
Local Group rest frame and ~330 km/s with respect to the cluster center.

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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
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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: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: eess