X-Ray Observations of the HESS Unidentified Sources from the Galactic Plane

Many bright TeV γ-ray objects have been discovered on the Galactic plane with the HESS telescope. We observed three of them, HESS J1614-518, HESS J1616-508, and HESS J1804-216 with the Suzaku satellite. We have found X-ray counterparts of HESS J1614 and HESS J1804, but their X-ray fluxes are quite low compared to their TeV fluxes. Their flux ratio of TeV to X-ray (f_TeV/f_X) is larger than 20, in contrast to typical γ-ray objects like the Crab nebula and RX J1713-3946. Thus these objects are good examples of dark particle accelerators, and cosmic ray protons may be accelerated in such objects.