Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Signs of Magnetic Accretion in the X-ray Pulsar Binary GX 301-2   Observations of the cyclotron resonance scattering feature in the X-ray
spectrum of GX 301-2 suggest that the surface field of the neutron star is
B_CRSF ~ 4 x 10^{12}G. The same value has been derived in modelling the rapid
spin-up episodes in terms of the Keplerian disk accretion scenario. However,
the spin-down rate observed during the spin-down trends significantly exceeds
the value expected in currently used spin-evolution scenarios. This indicates
that either the surface field of the star exceeds 50 x B_CRSF, or a currently
used accretion scenario is incomplete. We show that the above discrepancy can
be avoided if the accreting material is magnetized. The magnetic pressure in
the accretion flow increases more rapidly than its ram pressure and, under
certain conditions, significantly affects the accretion picture. The spin-down
torque applied to the neutron star in this case is larger than that evaluated
within a non-magnetized accretion scenario. We find that the observed spin
evolution of the pulsar can be explained in terms of the magnetically
controlled accretion flow scenario provided the surface field of the neutron
star is ~ B_CRSF.

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The categories of this paper are: comp-gas
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: funct-an
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The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
1
The categories of this paper are: cs
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: math
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The categories of this paper are: patt-sol
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg