Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A MERLIN Observation of PSR B1951+32 and its associated Plerion   In an investigative 16 hour L band observation using the MERLIN radio
interferometric array, we have resolved both the pulsar PSR B1951+32 and
structure within the flat spectral radio continuum region, believed to be the
synchrotron nebula associated with the interaction of the pulsar and its `host'
supernova remnant CTB 80. The extended structure we see, significant at $\sim$
4.5 $\sigma$, is of dimensions 2.5" $\times$ 0.75", and suggests a sharp bow
shaped arc of shocked emission, which is correlated with similar structure
observed in lower resolution radio maps and X-ray images. Using this MERLIN
data as a new astrometric reference for other multiwavelength data we can place
the pulsar at one edge of the HST reported optical synchrotron knot, ruling out
previous suggested optical counterparts, and allowing an elementary analysis of
the optical synchrotron emission which appears to trail the pulsar. The latter
is possibly a consequence of pulsar wind replenishment, and we suggest that the
knot is a result of magnetohydrodynamic (MHD) instabilities. These being so, it
suggests a dynamical nature to the optical knot, which will require high
resolution optical observations to confirm.

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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: math
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The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex