Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Is the Supernova Remnant RX J1713.7-3946 a Hadronic Cosmic Ray
  Accelerator ?   The non-thermal supernova remnant RX J1713.7-3946 (G347.3-0.5) has recently
been shown to be a site of cosmic ray (CR) electron acceleration to TeV
energies (Muraishi et al. 2000). Here we present evidence that this remnant is
also accelerating CR nuclei. Such nuclei can interact with ambient interstellar
gas to produce high energy gamma-rays via the decay of neutral pions. We
associate the unidentified EGRET GeV gamma- ray source 3EG J1714-3857 with a
massive (~3*10 5 Mo) and dense (~500 nucleons cm -3) molecular cloud
interacting with RX J1713.7-3946. Direct evidence for such interaction is
provided by observations of the lowest two rotational transitions of CO in the
cloud; as in other clear cases of interaction, the CO(J=2-1)/CO(J=1-0) ratio is
significantly enhanced. Since the cloud is of low radio and X-ray brightness,
CR electrons cannot be responsible for the bulk of its GeV emission there. A
picture thus emerges where both electrons and nuclei are being accelerated by
the SNR: whereas the CR electrons dominate the local non-thermal radio, X-ray
and TeV emission, the shock accelerated CR protons and ions (hadrons) are
revealed through their interactions in the adjacent massive cloud. Such a
scenario had been anticipated by Aharonian, Drury and Volk (1994).

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The categories of this paper are: cs
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The categories of this paper are: solv-int
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The categories of this paper are: cond-mat
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: chem-ph
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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: chao-dyn
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: eess
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The categories of this paper are: hep-ex