Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-Energy Activity in the Unusually Soft TeV Source HESS J1804-216
  toward the Galactic Center   In recent years, apparent anisotropies in the ~EeV cosmic ray (CR) flux
arriving at Earth from the general direction of the galactic center have been
reported from the analysis of AGASA and SUGAR data. The more recently
commissioned Auger Observatory has not confirmed these results. HESS has now
detected an unusually soft TeV source roughly coincident with the location of
the previously claimed CR anisotropy. In this paper, we develop a model for the
TeV emission from this object, consistent with observations at other
wavelengths, and examine the circumstances under which it might have
contributed to the $\sim$ EeV cosmic ray spectrum. We find that the supernova
remnant G8.7-0.1 can plausibly account for all the known radiative
characteristics of HESS J1804-216, but that it can accelerate cosmic rays only
up to an energy $\sim 10^5$ GeV. On the other hand, the pulsar (PSR J1803-2137)
embedded within this remnant can in principle inject EeV protons into the
surrounding medium, but it cannot account for the broadband spectrum of HESS
J1804-216. We therefore conclude that although G8.7-0.1 is probably the source
of TeV photons originating from this direction, there is no compelling
theoretical motivation for expecting a cosmic ray anisotropy at this location.
However, if G8.7-0.1 is indeed correctly identified with HESS J1804-216, it
should also produce a $\sim$ GeV flux detectable in a one-year all sky survey
by GLAST.

15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: stat
25
The categories of this paper are: patt-sol