Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Absorption of Very High Energy Gamma Rays in the Milky Way   Galactic Gamma ray astronomy at very high energy (E > 30 TeV) is a vital tool
in the study of the non-thermal universe. The interpretation of the
observations in this energy region requires the precise modeling of the
attenuation of photons due to pair production interactions, where the targets
are the radiation fields present in interstellar space. For gamma rays with
energy E > 300 TeV the attenuation is mostly due to the photons of the Cosmic
Microwave Background Radiation (CMBR). At lower energy the most important
target are infrared photons with wavelengths in the range 50-500 micron emitted
by dust. The evaluation of the attenuation requires a good knowledge of the
density, and energy and angular distributions of the target photons for all
positions in the Galaxy. In this work we discuss a simple model for the
infrared radiation that depends on only few parameters associated to the space
and temperature distributions of the emitting dust. The model allows to compute
with good accuracy the effects of absorption for any space and energy
distribution of the diffuse Galactic gamma ray emission. The absorption
probability due to the Galactic infrared radiation is maximum for E around 150
TeV, and can be as large as P_abs around 0.45 for distant sources on lines of
sight that pass close to the Galactic Center. The systematic uncertainties on
the absorption probability are estimated as Delta P_abs < 0.08.

2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int