Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The correlation between radio power and Mach number for radio relics in
  galaxy clusters   We discuss a new technique to constrain models for the origin of radio relics
in galaxy clusters using the correlation between the shock Mach number and the
radio power of relics. This analysis is carried out using a sample of relics
with information on both the Mach numbers derived from X-ray observation,
$\mathcal{M}_X$, and using spectral information from radio observations of the
peak and the average values of the spectral index along the relic,
$\mathcal{M}_R$. We find that there is a lack of correlation between
$\mathcal{M}_X$ and $\mathcal{M}_R$; this result is an indication that the
spectral index of the relic is likely not due to the acceleration of particles
operated by the shock but it is related to the properties of a fossil electrons
population. We also find that the available data on the correlation between the
radio power $P_{1.4}$ and Mach numbers ($\mathcal{M}_R$ and $\mathcal{M}_X$) in
relics indicate that neither the DSA nor the adiabatic compression can simply
reproduce the observed $P_{1.4}-\mathcal{M}$ correlations. Furthermore, we find
that the radio power is not correlated with $\mathcal{M}_X$, whereas it is not
possible to exclude a correlation with $\mathcal{M}_R$. This also indicates
that the relic power is mainly determined by the properties of a fossil
electron population rather than by the properties of the shock. Our results
require either to consider models of shock (re)acceleration that go beyond the
proposed scenarios of DSA and adiabatic compression at shocks, or to reconsider
the origin of radio relics in terms of other physical scenarios.

10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn