Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Redshift Survey of Nearby Galaxy Groups: the Shape of the Mass Density
  Profile   We constrain the mass profile and orbital structure of nearby groups and
clusters of galaxies. Our method yields the joint probability distribution of
the density slope n, the velocity anisotropy beta, and the turnover radius r0
for these systems. The measurement technique does not use results from N-body
simulations as priors. We incorporate 2419 new redshifts in the fields of 41
systems of galaxies with z < 0.04. The new groups have median velocity
dispersion sigma=360 km/s. We also use 851 archived redshifts in the fields of
8 nearly relaxed clusters with z < 0.1. Within R < 2 r200, the data are
consistent with a single power law matter density distribution with slope n =
1.8-2.2 for systems with sigma < 470 km/s, and n = 1.6-2.0 for those with sigma
> 470 km/s (95% confidence). We show that a simple, scale-free phase space
distribution function f(E,L^2) ~ (-E)^(alpha-1/2) L^(-2 \beta) is consistent
with the data as long as the matter density has a cusp. Using this DF, matter
density profiles with constant density cores (n=0) are ruled out with better
than 99.7% confidence.

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The categories of this paper are: quant-ph
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The categories of this paper are: nlin
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
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The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th