Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gaps in the GD-1 Star Stream   GD-1 is a long, thin, Milky Way star stream that has readily visible density
variations along its length. We quantify the locations, sizes and statistical
significance of the density structure, i.e. gaps, using a set of scaled
filters. The shapes of the filters are based on the gaps that develop in
simulations of dark matter sub-halos crossing a star stream. The high Galactic
latitude 8.4 kpc long segment of GD-1 that we examine has 8+/-3 gaps of 99%
significance or greater, with the error estimated on the basis of tests of the
gap-filtering technique. The cumulative distribution of gaps more than 3 times
the width of the stream is in good agreement with predictions for dark matter
sub-halo encounters with cold star streams. The number of gaps narrower than 3
times the width of the GD-1 stream falls well below the cold stream prediction
which is taken into account for the gap creation rate integrated over all
sizes. Simple warm stream simulations scaled to GD-1 show that the falloff in
gaps is expected for sub-halos below a mass of 10^6 M_sun. The GD-1 gaps
requires 100 sub-halos >10^6 M_sun within 30 kpc, the apocenter of GD-1 orbit.
These results are consistent with LCDM sub-halo predictions but further
improvements in stream signal-to-noise and gap modeling will be welcome.

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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
2
The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
1
The categories of this paper are: cs
3
The categories of this paper are: physics
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The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex