Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A tight scaling relation of dark matter in galaxy clusters   Recent studies in different types of galaxies reveal that the product of the
central density and the core radius ($\rho_cr_c$) is a constant. However, some
empirical studies involving galaxy clusters suggest that the product
$\rho_cr_c$ depends weakly on the total dark halo mass. In this article, we
re-analyse the hot gas data from 106 clusters and obtain a surprisingly tight
scaling relation: $\rho_c \propto r_c^{-1.46 \pm 0.16}$. This result generally
agrees with the claims that $\rho_cr_c$ is not a constant for all scales of
structure. Moreover, this relation does not support the velocity-dependent
cross section of dark matter if the core formation is due to the
self-interaction of dark matter.

31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an