Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Are Cluster Radio Relics Revived Fossil Radio Cocoons?   A new model for the, so called, `cluster radio relics' is presented (Ensslin
& Gopal-Krishna 2000). Fossil radio cocoons, resulting from the former activity
of radio galaxies, should contain a low energy relativistic electron population
and magnetic fields. Electrons with an age of even up to 2 Gyr can be
re-accelerated adiabatically to radio emitting energies, if the fossil radio
plasma gets compressed in an environmental shock wave. Such a wave can be
caused by a merging event of galaxy clusters, or by the accretion onto galaxy
clusters. An implication of this model is the existence of a population of
diffuse, ultra-steep spectrum, very low-frequency radio sources located inside
and possibly outside of clusters of galaxies, tracing the revival of aged
fossil radio plasma by the shock waves associated with large-scale structure
formation.

26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys