Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pulsed {\gamma}-ray emission from magnetar 1E 2259+586   Anomalous x-ray pulsars (AXPs) are thought to be magnetars which are young
isolated neutron stars with extremely strong magnetic fields of > 10^14Gauss.
Their tremendous magnetic fields inferred from the spin parameters provide a
huge energy reservoir to power the observed x-ray emission. High-energy
emission above 0.3 MeV has never been detected despite intensive search. Here,
we present the possible Fermi Large Area Telescope (LAT) detection of
{\gamma}-ray pulsations above 200 MeV from the AXP, 1E 2259+586, which puts the
current theoretical models of {\gamma}-ray emission mechanisms of magnetars
into challenge. We speculate that the high-energy {\gamma}-rays originate from
the outer magnetosphere of the magnetar.

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The categories of this paper are: hep-ph
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The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: nlin
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The categories of this paper are: q-bio
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The categories of this paper are: physics
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The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
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The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th