Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The puzzling source IGR J17361-4441 in NGC 6388: a possible planetary
  tidal disruption event   On 2011 August 11, INTEGRAL discovered the hard X-ray source IGR J17361-4441
near the centre of the globular cluster NGC 6388. Follow up observations with
Chandra showed the position of the transient was inconsistent with the cluster
dynamical centre, and thus not related to its possible intermediate mass black
hole. The source showed a peculiar hard spectrum (Gamma \approx 0.8) and no
evidence of QPOs, pulsations, type-I bursts, or radio emission. Based on its
peak luminosity, IGR J17361-4441 was classified as a very faint X-ray
transient, and most likely a low-mass X-ray binary. We re-analysed 200 days of
Swift/XRT observations, covering the whole outburst of IGR J17361-4441 and find
a t^{-5/3} trend evident in the light curve, and a thermal emission component
that does not evolve significantly with time. We investigate whether this
source could be a tidal disruption event, and for certain assumptions find an
accretion efficiency epsilon \approx 3.5E-04 (M_{Ch}/M) consistent with a
massive white dwarf, and a disrupted minor body mass M_{mb}=1.9E+27(M/M_{Ch}) g
in the terrestrial-icy planet regime. These numbers yield an inner disc
temperature of the order kT_{in} \approx 0.04 keV, consistent with the
blackbody temperature of kT_{in} \approx 0.08 keV estimated by spectral
fitting. Although the density of white dwarfs and the number of free-floating
planets are uncertain, we estimate the rate of planetary tidal disruptions in
NGC 6388 to be in the range 3E-06 to 3E-04 yr^{-1}. Averaged over the Milky Way
globular clusters, the upper limit value corresponds to 0.05 yr^{-1},
consistent with the observation of a single event by INTEGRAL and Swift.

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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int