Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An extended Pal 5 stream in Gaia DR2   We present the results of a detailed search for members of the Pal 5 tidal
tail system in Gaia Data Release 2 (DR2). Tidal tails provide a sensitive
method for measuring the current and past gravitational potential of their host
galaxy as well as for testing predictions for the abundance of dark matter
subhalos. The Pal 5 globular cluster and its associated tails are an excellent
candidate for such analysis; however, only ~23 degrees of arc are currently
known, with in particular the leading tail much shorter than the trailing.
Using Gaia DR2 and its precise astrometry, we extend the known extent of the
Pal 5 tail to ~30 degrees, 7 degrees of which are newly detected along the
leading arm. The detected leading and trailing arms are symmetric in length and
remain near constant width. This detection constrains proposed models in which
the Galactic bar truncates Pal 5's leading arm. Follow-up spectroscopic
observations are necessary to verify the candidate stream stars are consistent
with the known tidal tails. If confirmed, this Pal 5 stream extension opens up
new possibilities to constrain the Galactic potential.

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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
2
The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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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: math-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn