Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Shape of Dark Matter Haloes in the Aquarius Simulations: Evolution
  and Memory   We use the high resolution cosmological N-body simulations from the Aquarius
project to investigate in detail the mechanisms that determine the shape of
Milky Way-type dark matter haloes. We find that, when measured at the
instantaneous virial radius, the shape of individual haloes changes with time,
evolving from a typically prolate configuration at early stages to a more
triaxial/oblate geometry at the present day. This evolution in halo shape
correlates well with the distribution of the infalling material: prolate
configurations arise when haloes are fed through narrow filaments, which
characterizes the early epochs of halo assembly, whereas triaxial/oblate
configurations result as the accretion turns more isotropic at later times.
Interestingly, at redshift z=0, clear imprints of the past history of each halo
are recorded in their shapes at different radii, which also exhibit a variation
from prolate in the inner regions to triaxial/oblate in the outskirts. Provided
that the Aquarius haloes are fair representatives of Milky Way-like 10^12 Msun
objects, we conclude that the shape of such dark matter haloes is a complex,
time-dependent property, with each radial shell retaining memory of the
conditions at the time of collapse.

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The categories of this paper are: math-ph
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The categories of this paper are: q-alg
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The categories of this paper are: econ
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The categories of this paper are: ao-sci
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The categories of this paper are: eess
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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: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys