Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Intrinsic absorption in 3C 279 at GeV-TeV energies and consequences for
  estimates of the EBL   We revisit the limits of the level of the extragalactic background light
(EBL) recently reported by the MAGIC collaboration based on the observed
gamma-ray spectrum of the quasar 3C279, considering the impact of absorption of
high-energy gamma-ray photons inside the broad line region (BLR) of the quasar.
We use the photoionization code CLOUDY to calculate the expected optical-UV
radiation field inside the BLR and the optical depth to gamma-rays for a
relatively extended set of the parameters. We found that the absorption of
gamma-ray photons, though important for the estimate of the true radiative
output of the source, does not produce an important hardening of the spectrum
of 3C279 in the energy band accessible by MAGIC, supporting the method used to
infer the upper limits to the level of the EBL.

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The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th