Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Evolution of X-ray Clusters in Low Density Universes   We present results of N-body/gasdynamical simulations designed to investigate
the evolution of X-ray clusters in a flat, low-density, cold dark matter (CDM)
cosmogony. The density profile of the dark matter component can be fitted
rather accurately by the simple formula originally proposed by Navarro, Frenk &
White to describe the structure of clusters in a CDM universe with $\Omega=1$.
In projection, the shape of the dark matter radial density profile and the
corresponding line-of-sight velocity dispersion profile are in very good
agreement with the observed profiles for galaxies in the CNOC sample of
clusters. The gas in our simulated clusters is less centrally concentrated than
the dark matter, and its radial density profile is well described by the
familiar $\beta$-model. The total mass and velocity dispersion of our clusters
can be accurately inferred (with $\sim 15%$ uncertainty) from their X-ray
emission-weighted temperature. We generalize Kaiser's scaling relations for
scale-free universes and show that the clusters in our simulations generally
follow these relations. The agreement between the simulations and the
analytical results provides a convincing demonstration of the soundness of our
gasdynamical numerical techniques. The slope of the luminosity-temperature
relation implied by the scaling relations, and obeyed by the simulations, is in
disagreement with observations. This suggests that non-gravitational effects
such as preheating or cooling must have played an important role in determining
the properties of the observed X-ray emission from galaxy clusters.

23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn