We observed the bright unidentified TeV \gamma -ray source HESS J1616 - 508 with the X-ray Imaging Spectrometers onboard the Suzaku satellite .
No X-ray counterpart was found to a limiting flux of 3.1 \times 10 ^ { -13 } erg s ^ { -1 } cm ^ { -2 } in the 2–10 keV band , which is some 60 times below the \gamma -ray flux in the 1–10 TeV band .
This object is bright in TeV \gamma -rays but very dim in the X-ray band , and thus is one of the best examples in the Galaxy of a ” dark particle accelerator. ” We also detected soft thermal emission with kT \sim 0.3–0.6 keV near the location of HESS J1616 - 508 .
This may be due to the dust grain scattering halo from the nearby bright supernova remnant RCW 103 .