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 .