Title: HESS J1826$-$130: A Very Hard $γ$-Ray Spectrum Source in the Galactic Plane,
Abstract: HESS J1826$-$130 is an unidentified hard spectrum source discovered by
H.E.S.S. along the Galactic plane, the spectral index being $\Gamma$ = 1.6 with
an exponential cut-off at about 12 TeV. While the source does not have a clear
counterpart at longer wavelengths, the very hard spectrum emission at TeV
energies implies that electrons or protons accelerated up to several hundreds
of TeV are responsible for the emission. In the hadronic case, the VHE emission
can be produced by runaway cosmic-rays colliding with the dense molecular
clouds spatially coincident with the H.E.S.S. source.