Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Absolute Proper Motion of Palomar 12: A Case for Tidal Capture from
  the Sagittarius Dwarf Spheroidal Galaxy   We have measured the absolute proper motion of the young globular cluster Pal
12 with respect to background galaxies, using plate material spanning a 40-year
time baseline, and measuring stars down to a magnitude V~22. The measured
absolute proper motion has an uncertainty of 0.3 mas/yr in each coordinate.
  Pal 12's young age for a globular cluster led to the hypothesis that the
cluster originated in the Large Magellanic Cloud (LMC) and was later captured
by the Milky Way (Lin and Richer 1992). Here we investigate this hypothesis
using the complete kinematical data. We present the orbital characteristics of
Pal 12 and compare them with those of the LMC and Sagittarius dwarf galaxy
(Sgr). The present kinematical data suggest that, from the two parent
candidates for Pal 12, Sgr presents a more plausible case for the host galaxy
than the LMC.
  We explore this scenario in the context of the uncertainties in the orbits
and using two different analyses: the direct comparison of the orbits of Pal 12
and Sgr as a function of time, and the analytical model of Sgr's tidal
disruption developed by Johnson (1998). We find that, within the present
uncertainties of the observables, this scenario is viable in both methods.
Moreover, both methods place this event at the same point in time. Our best
estimate of the time of Pal 12's tidal capture from Sgr is ~ 1.7 Gyr ago.

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The categories of this paper are: comp-gas
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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: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: physics
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The categories of this paper are: q-bio