Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Particle Content of Extragalactic Jets   Recent x-ray and radio data from radio sources in galaxy clusters are used to
show that the pdV work required to inflate the radio lobes exceeds all other
energy estimates deduced from the radio emission. If the required jet energy
density has an isotropic pressure, then in almost all cases the jet cannot be
confined by an external medium. This problem can be resolved with jets
dominated by cold protons, but even here the accompanying energy density in
relativistic electons can cause decollimation. Electron-positron jets cannot
solve this problem unless they are highly beamed with unusual energy
distributions. Poynting flux jets may be a viable alternative.

8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org