Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: HETE-2 Localization and Observations of the Gamma-Ray Burst GRB 020813   A bright, long gamma-ray burst (GRB) was detected and localized by the
instruments on board the High Energy Transient Explorer 2 satellite (HETE-2) at
02:44:19.17 UTC (9859.17 s UT) on 2002 August 13. The location was reported to
the GRB Coordinates Network (GCN) about 4 min after the burst. In the prompt
emission, the burst had a duration of approximately 125 s, and more than four
peaks. We analyzed the time-resolved 2-400 keV energy spectra of the prompt
emission of GRB 020813 using the Wide Field X-Ray Monitor (WXM) and the French
Gamma Telescope (FREGATE) in detail. We found that the early part of the burst
(17-52 s after the burst trigger) shows a depletion of low-energy photons below
about 50 keV. It is difficult to explain the depletion with by either
synchrotron self-absorption or Comptonization. One possibility is that the
low-energy depletion may be understood as a mixture of ``jitter'' radiation the
usual synchrotron radiation component.

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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: nlin
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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: acc-phys
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int