Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radio signature of cosmological structure formation shocks   In the course of the formation of cosmological structures, large shock waves
are generated in the intra-cluster medium. In analogy to processes in supernova
remnants, these shock waves may generate a significant population of
relativistic electrons which, in turn, produce observable synchrotron emission.
The extended radio relics found at the periphery of several clusters and
possibly also a fraction of radio halo emission may have this origin. Here we
derive an analytic expression for (i) the total radio power in the downstream
region of a cosmological shock wave and (ii) the width of the radio-emitting
region. These expressions predict a spectral slope close to -1 for strong
shocks. Moderate shocks, such as those produced in mergers between clusters of
galaxies, lead to a somewhat steeper spectrum. Moreover, we predict an upper
limit for the radio power of cosmological shocks. Comparing our results to the
radio relics in Abell115, 2256, and 3667, we conclude that the magnetic field
in these relics is typically at a level of 0.1 mu G. Magnetic fields in the
intra-cluster medium are presumably generated by the shocks themselves, this
allows us to calculate the radio emission as a function of the cluster
temperature. The resulting emissions agree very well with the radio
power-temperature relation found for cluster halos. Finally, we show that
cosmic accretion shocks generate less radio emission than merger shock waves.
The latter may, however, be detected with upcoming radio telescopes.

9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci