Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lowly polarized light from a highly magnetized jet of GRB 190114C   We report multi-color optical imaging and polarimetry observations of the
afterglow of the first TeV- detected gamma-ray burst, GRB 190114C, using RINGO3
and MASTER II polarimeters. Observations begin 31 s after the onset of the GRB
and continue until $\sim 7000\,$s post-burst. The light curves reveal a
chromatic break at $\sim 400- 500\,$s, with initial temporal decay $\alpha =
1.669 \pm 0.013$ flattening to $\alpha \sim 1$ post-break, which we model as a
combination of reverse and forward-shock components, with magnetization
parameter $R_{\rm B} \sim 70$. The observed polarization degree decreases from
$7.7 \pm 1.1\%$ to $2-4\%$ during $52-109\,$s post-burst and remains steady at
this level for the subsequent $\sim 2000$-s, at constant position angle.
Broadband spectral energy distribution modeling of the afterglow confirms GRB
190114C is highly obscured (A$_{\rm v, HG} = 1.49 \pm 0.12 \,$mag; N$_{\rm H,
HG}= (9.0 \pm 0.3) \times 10^{22}\,$cm$^{-2}$). We interpret the measured
afterglow polarization as intrinsically low and dominated by dust, in contrast
to ${\rm P} >10\%$ measured previously for other GRB reverse shocks, with a
small contribution from polarized prompt photons in the first minute. We test
whether 1st and higher-order inverse Compton scattering in a magnetized reverse
shock can explain the low optical polarization and the sub-TeV emission but
conclude neither is explained in the reverse shock Inverse Compton model.
Instead, the unexpectedly low intrinsic polarization degree in GRB 190114C can
be explained if large-scale jet magnetic fields are distorted on timescales
prior to reverse shock emission.

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The categories of this paper are: q-bio
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: math
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The categories of this paper are: hep-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: nlin
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The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th