Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Globular Cluster Toward M87 with a Radial Velocity < -1000 km/s: The
  First Hypervelocity Cluster   We report the discovery of an object near M87 in the Virgo Cluster with an
extraordinary blueshift of -1025 km/s, offset from the systemic velocity by
>2300 km/s. Evaluation of photometric and spectroscopic data provides strong
evidence that this object is a distant massive globular cluster, which we call
HVGC-1 in analogy to Galactic hypervelocity stars. We consider but disfavor
more exotic interpretations, such as a system of stars bound to a recoiling
black hole. The odds of observing an outlier as extreme as HVGC-1 in a
virialized distribution of intracluster objects are small; it appears more
likely that the cluster was (or is being) ejected from Virgo following a
three-body interaction. The nature of the interaction is unclear, and could
involve either a subhalo or a binary supermassive black hole at the center of
M87.

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The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an