Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the origin of supergiant fast X-ray transients   A fraction of high-mass X-ray binaries are supergiant fast X-ray transients.
These systems have on average low X-ray luminosities, but display short flares
during which their X-ray luminosity rises by a few orders of magnitude. The
leading model for the physics governing this X-ray behaviour suggests that the
winds of the donor OB supergiants are magnetized. In agreement with this model,
the first spectropolarimetric observations of the SFXT IGR J11215-5952 using
the FORS2 instrument at the Very Large Telescope indicate the presence of a kG
longitudinal magnetic field. Based on these results, it seems possible that the
key difference between supergiant fast X-ray transients and other high-mass
X-ray binaries are the properties of the supergiant's stellar wind and the
physics of the wind's interaction with the neutron star magnetosphere.

29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn