Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gamma-Gamma Absorption in the Broad Line Region Radiation Fields of
  Gamma-Ray Blazars   The expected level of gamma-gamma absorption in the Broad Line Region (BLR)
radiation field of gamma-ray loud Flat Spectrum Radio Quasars (FSRQs)is
evaluated as a function of the location of the gamma-ray emission region. This
is done self-consistently with parameters inferred from the shape of the
spectral energy distribution (SED) in a single-zone leptonic EC-BLR model
scenario. We take into account all geometrical effects both in the calculation
of the gamma-gamma opacity and the normalization of the BLR radiation energy
density. As specific examples, we study the FSRQs 3C279 and PKS 1510-089,
keeping the BLR radiation energy density at the location of the emission region
fixed at the values inferred from the SED. We confirm previous findings that
the optical depth due to $\gamma\gamma$ absorption in the BLR radiation field
exceeds unity for both 3C279 and PKS 1510-089 for locations of the gamma-ray
emission region inside the inner boundary of the BLR. It decreases
monotonically, with distance from the central engine and drops below unity for
locations within the BLR. For locations outside the BLR, the BLR radiation
energy density required for the production of GeV gamma-rays rapidly increases
beyond observational constraints, thus making the EC-BLR mechanism implausible.
Therefore, in order to avoid significant gamma-gamma absorption by the BLR
radiation field, the gamma-ray emission region must therefore be located near
the outer boundary of the BLR.

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The categories of this paper are: plasm-ph
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: stat
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The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: cs
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The categories of this paper are: solv-int