Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The discovery of weak coherent pulsations in the ultraluminous X-ray
  source NGC 1313 X-2   We report the detection of weak pulsations from the archetypal ultraluminous
X-ray source (ULX) NGC 1313 X-2. Acceleration searches reveal sinusoidal
pulsations in segments of two out of six new deep observations of this object,
with a period of $\sim$ 1.5 s and a pulsed fraction of $\sim$ 5%. We use Monte
Carlo simulations to demonstrate that the individual detections are unlikely to
originate in false Poisson noise detections given their very close frequencies;
their strong similarity to other pulsations detected from ULXs also argues they
are real. The presence of a large bubble nebula surrounding NGC 1313 X-2
implies an age of order 1 Myr for the accreting phase of the ULX, which implies
that the neutron star's magnetic field has not been suppressed over time by
accreted material, nor has the neutron star collapsed into a black hole,
despite an average energy output into the nebula two orders of magnitude above
Eddington. This argues that most of the accreted material has been expelled
over the lifetime of the ULX, favouring physical models including strong winds
and/or jets for neutron star ULXs.

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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
2
The categories of this paper are: math
1
The categories of this paper are: cs
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The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: supr-con
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The categories of this paper are: eess
14
The categories of this paper are: math-ph