Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: No evidence for gamma-ray halos around active galactic nuclei resulting
  from intergalactic magnetic fields
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
19
The categories of this paper are: eess