Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Simple and Accurate Model for Intra-Cluster Gas   Starting with the well-known NFW dark matter halo distribution, we construct
a simple polytropic model for the intracluster medium which is in good
agreement with high resolution numerical hydrodynamical simulations, apply this
model to a very large scale concordance dark matter simulation, and compare the
resulting global properties with recent observations of X-ray clusters,
including the mass-temperature and luminosity-temperature relations. We make
allowances for a non-negligible surface pressure, removal of low entropy (short
cooling time) gas, energy injection due to feedback, and for a relativistic
(non-thermal) pressure component. A polytropic index n=5 (Gamma=1.2) provides a
good approximation to the internal gas structure of massive clusters (except in
the very central regions where cooling becomes important), and allows one to
recover the observed M_500-T, L_x-T, and T/n_e^{2/3} ~ T^0.65 relations. Using
these concepts and generalizing this method so that it can be applied to fully
three-dimensional N-body simulations, one can predict the global X-ray and SZE
trends for any specified cosmological model. We find a good fit to observations
when assuming that twelve percent of the initial baryonic mass condenses into
stars, the fraction of rest mass of this condensed component transferred back
to the remaining gas (feedback) is 3.9E-5, and the fraction of total pressure
from a nonthermal component is near ten percent.

23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con