Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pieces of the puzzle: Ancient substructure in the Galactic disk   We search for signatures of past accretion events in the Milky Way in the
recently published catalogue by Nordstrom et al.(2004), containing accurate
spatial and kinematic information as well as metallicities for 13240 nearby
stars. To optimize our strategy, we use numerical simulations to characterize
the properties of the debris from disrupted satellites. We find that stars with
a common progenitor should show distinct correlations between their orbital
parameters; in particular, between the apocentre A and pericentre P, as well as
their z-angular momentum (L_z). In the APL-space, such stars are expected to
cluster around regions of roughly constant eccentricity.
  The APL space for the Nordstrom catalogue exhibits a wealth of substructure,
much of which can be linked to dynamical perturbations induced by spiral arms
and the Galactic bar. However, our analysis also reveals a statistically
significant excess of stars on orbits of common (moderate) eccentricity,
analogous to the pattern expected for merger debris. Besides being dynamically
peculiar, the 274 stars in these substructures have very distinct metallicity
and age distributions, providing further evidence of their extra-Galactic
provenance. It is possible to identify among these stars, three coherent Groups
with characteristic ages and metallicities, that, in all likelihood, correspond
to the remains of disrupted satellites. [abridged]

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The categories of this paper are: hep-ex
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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: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: quant-ph
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The categories of this paper are: cs
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The categories of this paper are: physics
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ph
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: econ