Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectral signature of a free pulsar wind in the gamma-ray binaries LS
  5039 and LSI +61$\degr$303   LS 5039 and LSI +61$\degr$303 are two binaries that have been detected in the
TeV energy domain. These binaries are composed of a massive star and a compact
object, possibly a young pulsar. The gamma-ray emission would be due to
particle acceleration at the collision site between the relativistic pulsar
wind and the stellar wind of the massive star. Part of the emission may also
originate from inverse Compton scattering of stellar photons on the unshocked
(free) pulsar wind. The purpose of this work is to constrain the bulk Lorentz
factor of the pulsar wind and the shock geometry in the compact pulsar wind
nebula scenario for LS 5039 and LSI +61$\degr$303 by computing the unshocked
wind emission and comparing it to observations. Anisotropic inverse Compton
losses equations are derived and applied to the free pulsar wind in binaries.
The unshocked wind spectra seen by the observer are calculated taking into
account the gamma-gamma absorption and the shock geometry. A pulsar wind
composed of monoenergetic pairs produces a typical sharp peak at an energy
which depends on the bulk Lorentz factor and whose amplitude depends on the
size of the emitting region. This emission from the free pulsar wind is found
to be strong and difficult to avoid in LS 5039 and LSI +61$\degr$303. If the
particles in the pulsar are monoenergetic then the observations constrain their
energy to roughly 10-100 GeV. For more complex particle distributions, the free
pulsar wind emission will be difficult to distinguish from the shocked pulsar
wind emission.

14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
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The categories of this paper are: econ
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph