Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A possible cyclotron resonance scattering feature near 0.7 keV in
  X1822-371   We analyse all available X-ray observations of X1822-371 made with
XMM-Newton, Chandra, Suzaku and INTEGRAL satellites. The observations were not
simultaneous. The Suzaku and INTEGRAL broad band energy coverage allows us to
constrain the spectral shape of the continuum emission well. We use the model
already proposed for this source, consisting of a Comptonised component
absorbed by interstellar matter and partially absorbed by local neutral matter,
and we added a Gaussian feature in absorption at $\sim 0.7$ keV. This addition
significantly improves the fit and flattens the residuals between 0.6 and 0.8
keV. We interpret the Gaussian feature in absorption as a cyclotron resonant
scattering feature (CRSF) produced close to the neutron star surface and derive
the magnetic field strength at the surface of the neutron star, $(8.8 \pm 0.3)
\times 10^{10}$ G for a radius of 10 km. We derive the pulse period in the
EPIC-pn data to be 0.5928850(6) s and estimate that the spin period derivative
of X1822-371 is $(-2.55 \pm 0.03) \times 10^{-12}$ s/s using all available
pulse period measurements. Assuming that the intrinsic luminosity of
X1822-371is at the Eddington limit and using the values of spin period and spin
period derivative of the source, we constrain the neutron star and companion
star masses. We find the neutron star and the companion star masses to be $1.69
\pm 0.13$ M$_{\odot}$ and $0.46 \pm 0.02$ M$_{\odot}$, respectively, for a
neutron star radius of 10 km.In a self-consistent scenario in which X1822-371
is spinning-up and accretes at the Eddington limit, we estimate that the
magnetic field of the neutron star is $(8.8 \pm 0.3) \times 10^{10}$ G for a
neutron star radius of 10 km. If our interpretation is correct, the Gaussian
absorption feature near 0.7 keV is the very first detection of a CRSF below 1
keV in a LMXB. (abridged)

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The categories of this paper are: stat
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The categories of this paper are: cs
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The categories of this paper are: cond-mat
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The categories of this paper are: nlin
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: q-bio
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The categories of this paper are: ao-sci
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The categories of this paper are: patt-sol
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The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int