Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fermi-LAT Detection of a Hard Spectrum Flare from the Gravitationally
  Lensed Blazar B0218+357   The Fermi-LAT has observed new gamma-ray flares from the blazar B0218+357
during July 2014. While no significant change in the gamma-ray spectrum has
been previously observed through the flaring phase in late-2012, during this
recent high activity the source displayed an exceptionally hard spectrum. The
latter led to the detection of very high energy (VHE, E > 100 GeV) gamma-rays
from B0218+357 by the MAGIC telescopes, establishing this source as the most
distant TeV emitter known to date. In addition to the detection of VHE
emission, this blazar is of particular interest since it is known to be a
double-image gravitationally lensed system with a lens delay of 11.46 +/- 0.16
days measured in gamma-rays. We present the Fermi-LAT study of the July 2014
flares and discuss them in the context of previous measurements.

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The categories of this paper are: mtrl-th
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The categories of this paper are: chem-ph
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: econ
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex