Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: One large blob and many streams frosting the nearby stellar halo in Gaia
  DR2   We explore the phase-space structure of nearby halo stars identified
kinematically from Gaia DR2 data. We focus on their distribution in velocity
and in "integrals of motion" space as well as on their photometric properties.
Our sample of stars selected to be moving at a relative velocity of at least
210 km/s with respect to the Local Standard of Rest, contains an important
contribution from the low rotational velocity tail of the disk(s). The
$V_R$-distribution of these stars depicts a small asymmetry similar to that
seen for the faster rotating thin disk stars near the Sun. We also identify a
prominent, slightly retrograde "blob", which traces the metal-poor halo main
sequence reported by Gaia Collaboration et al. (2018d). We also find many small
clumps especially noticeable in the tails of the velocity distribution of the
stars in our sample. Their HR diagrams disclose narrow sequences characteristic
of simple stellar populations. This stream-frosting confirms predictions from
cosmological simulations, namely that substructure is most apparent amongst the
fastest moving stars, typically reflecting more recent accretion events.

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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: physics
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn