Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Swift/XRT monitoring of the candidate Supergiant Fast X-ray Transient
  IGR J16418-4532   We report on the Swift monitoring of the candidate supergiant fast X-ray
transient (SFXT) IGR J16418-4532, for which both orbital and spin periods are
known (~3.7d and ~1250s, respectively). Our observations, for a total of ~43ks,
span over three orbital periods and represent the most intense and complete
sampling of the light curve of this source with a sensitive X-ray instrument.
With this unique set of observations we can address the nature of this
transient. By applying the clumpy wind model for blue supergiants to the
observed X-ray light curve, and assuming a circular orbit, the X-ray emission
from this source can be explained in terms of the accretion from a spherically
symmetric clumpy wind, composed of clumps with different masses, ranging from
~5E16 g to 1E21g. Our data suggest, based on the X-ray behaviour, that this is
an intermediate SFXT.

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The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas
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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an
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The categories of this paper are: cond-mat
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex