Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin evolution of long-period X-ray pulsars   Spin evolution of X-ray pulsars in High Mass X-ray Binaries (HMXBs) is
discussed under various assumptions about the geometry and physical parameters
of the accretion flow. The torque applied to the neutron star from the
accretion flow and equilibrium period of the pulsars are evaluated. We show
that the observed spin evolution of the pulsars can be explained in terms of a
scenario in which the neutron star accretes material from a magnetized stellar
wind.

25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con