Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: VLBI and Archival VLA and WSRT Observations of the GRB 030329 Radio
  Afterglow   We present VLBI and archival Karl G. Jansky Very Large Array (VLA) and
Westerbork Synthesis Radio Telescope (WSRT) observations of the radio afterglow
from the gamma-ray burst (GRB) of 2003 March 29 (GRB 030329) taken between 672
and 2032 days after the burst. The EVLA and WSRT data suggest a simple power
law decay in the flux at 5 GHz, with no clear signature of any rebrightening
from the counter jet. We report an unresolved source at day 2032 of size
$1.18\pm0.13$ mas, which we use in conjunction with the expansion rate of the
burst to argue for the presence of a uniform, ISM-like circumburst medium.
  We develop a semi-analytic method to model gamma-ray burst afterglows, and
apply it to the 5 GHz light curve to perform burst calorimetry. A limit of $<
0.067$ mas yr$^{-1}$ is placed on the proper motion, supporting the standard
afterglow model for gamma-ray bursts.

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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: acc-phys
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The categories of this paper are: q-alg