Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radio Observations of the Supernova Remnant Candidate G312.5-3.0   The radio images from the Parkes-MIT-NRAO (PMN) Southern Sky Survey at 4850
MHz have revealed a number of previously unknown radio sources. One such
source, G312.5-3.0 (PMN J1421-6415), has been observed using the
multi-frequency capabilities of the Australia Telescope Compact Array (ATCA) at
frequencies of 1380 MHz and 2378 MHz. Further observations of the source were
made using the Molonglo Observatory Synthesis Telescope (MOST) at a frequency
of 843 MHz. The source has an angular size of 18 arcmin and has a distinct
shell structure. We present the reduced multi-frequency observations of this
source and provide a brief argument for its possible identification as a
supernova remnant.

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The categories of this paper are: adap-org
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The categories of this paper are: physics
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The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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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: supr-con
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: math