Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Potential PeVatron supernova remnant G106.3+2.7 seen in the
  highest-energy gamma rays   Cosmic rays (protons and other atomic nuclei) are believed to gain energies
of petaelectronvolts (PeV) and beyond at astrophysical particle accelerators
called 'PeVatrons' inside our Galaxy. Although a characteristic feature of a
PeVatron is expected to be a hard gamma-ray energy spectrum that extends beyond
100 teraelectronvolts (TeV) without a cutoff, none of the currently known
sources exhibits such a spectrum due to the low maximum energy of accelerated
cosmic rays or insufficient detector sensitivity around 100 TeV. Here we report
the observation of gamma-ray emission from the supernova remnant G106.3+2.7
above 10 TeV. This work provides flux data points up to and above 100 TeV and
indicates that the very-high-energy gamma-ray emission above 10 TeV is well
correlated with a molecular cloud rather than the pulsar PSR J2229+6114.
Regarding the gamma-ray emission mechanism of G106.3+2.7, this morphological
feature appears to favor a hadronic origin via the {\pi}0 decay caused by
accelerated relativistic protons over a leptonic one via the inverse-Compton
scattering by relativistic electrons. Furthermore, we point out that an X-ray
flux upper limit on the synchrotron spectrum would provide important
information to firmly establish the hadronic scenario as the mechanism of
particle acceleration at the source.

16
The categories of this paper are: stat
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
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The categories of this paper are: econ
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio