Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Slicing and dicing the Milky Way disk in SDSS   We use the Stripe 82 proper motion catalogue of Bramich et al. (2008) to
study the kinematics of Galactic disk stars in the solar neighborhood. We
select samples of dwarf stars with reliable spectra and proper motions. They
have cylindrical polar radius between 7 < R < 9 kpc, heights from the Galactic
plane satisfying z < 2 kpc and span a range of metallicities -1.5 < [Fe/H] < 0.
We develop a method for calculating and correcting for the halo contamination
in our sample using the distribution of rotational velocities. Two Gaussians
representing disk and halo populations are used to fit the radial and vertical
velocity distributions via maximum likelihood methods. For the azimuthal
velocities the same technique is used, except that a skewed non-Gaussian
functional form now represents the disk velocity distribution. This enables us
to compute the dispersions and cross-terms (the tilt and the vertex deviation)
of the velocity ellipsoid as a function of height and metallicity. We also
investigate the rotation lag of the disk, finding that the more metal-poor
stars rotate significantly slower than the metal-rich stars. These samples
provide important constraints on heating mechanisms in the Galactic disk and
can be used for a variety of applications. We present one such application,
employing the Jeans equations to provide a simple model of the potential close
to the disk. Our model is in excellent agreement with others in the literature
and provides an indication the disk, rather than the halo, dominates the
circular speed at the solar neighborhood. We obtain a surface mass density
within 1.1 kpc of around 66 M/pc^2 and estimate a local halo density of 0.015
M/pc^3 = 0.57 GeV/cm^3.

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The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
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The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
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The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th