Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Precession Interpretation of the Isolated Pulsar PSR B1828-11   Pulse timing of the isolated pulsar PSR B1882-11 shows strong Fourier power
at periods ~1000, 500 and 250 d, correlated with changes in the pulse profile
(Stairs, Lyne & Shemar 2000). We study the extent to which these data can be
explained by precession of the star's rigid crust coupled to the magnetic
dipole torque. We find that the correlated changes in the pulse duration and
spin period derivative can be explained as precession at a period of ~500 d
with a wobble angle of ~3 deg if the star's dipole moment is nearly orthogonal
to its symmetry axis. The dipole torque produces a harmonic at ~250 d.
Comparison of the predicted spin dynamics with the observed pulse durations
requires the radio beam to have a non-standard ``hour-glass'' shape. We make
predictions of variations in beam polarization and pulse profile with which to
test this interpretation. The precession interpretation of PSR B1828-11
seriously challenges the current understanding of the liquid interior of the
neutron star. In particular, if the internal liquid is in a superfluid state,
its rotational vortices cannot be significantly pinned to the crust.

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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ph
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The categories of this paper are: q-fin
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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: nlin
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat