Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First Detection of Radio Linear Polarization in a Gamma Ray Burst
  Afterglow   We report the first detection of radio polarization of a GRB afterglow with
the first intensive combined use of telescopes in the millimeter and
submillimeter ranges for GRB171205A. The linear polarization degree in the
millimeter band at the sub-percent level ($0.27 \pm 0.04\%$) is lower than
those observed in late-time optical afterglows (weighted average of $\sim
1\%$). The Faraday depolarization by non-accelerated, cool electrons in the
shocked region is one of possible mechanisms for the low value. In this
scenario, larger total energy by a factor of $\sim 10$ than ordinary estimate
without considering non-accelerated electrons is required. The polarization
position angle varies by at least 20 degrees across the millimeter band, which
is not inconsistent with this scenario. This result indicates that polarimetry
in the millimeter and submillimeter ranges is a unique tool for investigating
GRB energetics, and coincident observations with multiple frequencies or bands
would provide more accurate measurements of the non-accelerated electron
fraction.

37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat