Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The long-term post-outburst spin down and flux relaxation of magnetar
  Swift J1822.3$-$1606   The magnetar Swift J1822.3$-$1606 entered an outburst phase in 2011 July.
Previous X-ray studies of its post-outburst rotational evolution yielded
inconsistent measurements of the spin-inferred magnetic field. Here we present
the timing behavior and flux relaxation from over two years of Swift, XTE, and
Chandra observations following the outburst. We find that the ambiguity in
previous timing solutions was due to enhanced spin down that resembles an
exponential recovery following a glitch at the outburst onset. After fitting
out the effects of the recovery, we measure a long-term spin-down rate of
$\dot\nu=(-3.0\pm0.3)\times10^{-8}$ s$^{-2}$ which implies a dipolar magnetic
field of $1.35\times10^{13}$ G, lower than all previous estimates for this
source. We also consider the post-outburst flux evolution, and fit it with both
empirical and crustal cooling models. We discuss the flux relaxation in the
context of both crustal cooling and magnetospheric relaxation models.

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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: q-alg
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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: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: cs
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The categories of this paper are: dg-ga