Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Remarkably Loud Quasi-Periodicity after a Star is Disrupted by a
  Massive Black Hole   The immense tidal forces of massive black holes can rip apart stars that come
too close to them. As the resulting stellar debris spirals inwards, it heats up
and emits x-rays when near the black hole. Here, we report the discovery of an
exceptionally stable 131-second x-ray quasi-periodicity from a black hole after
it disrupted a star. Using a black hole mass indicated from host galaxy scaling
relations implies that, (1) this periodicity originates from very close to the
black hole's event horizon, and (2) the black hole is rapidly spinning. Our
findings suggest that other disruption events with similar highly sensitive
observations likely also exhibit quasi-periodicities that encode information
about the fundamental properties of their black holes.

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The categories of this paper are: q-bio
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The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an