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SUZAKU X-ray Image of HESS J1809-193 in the 2-10 keV band. This figure is taken from Anada et al. 2010, PASJ. You can check SUZAKU and AKARI data using our JUDO.

Mystery of unidentified HESS sources revealed by ASCA and SUZAKU

One of the most exciting moments for an astronomer is to discover an unknown source and reveal its mystery. HESS unidentified sources are recent such hot targets. These are very-high-energy gamma-ray sources discovered by the H.E.S.S telescope but with no counterparts in other wavelengths. The H.E.S.S. Cherenkov telescope is capable to catch gamma-ray having more than 1,000,000,000,000 electron bolts, or TeV. Today (now in 2011), about 40 such unidentified sources are known. To reveal and understand the origin of these sources, scientists have pointed their telescopes to them extensively. Now, the figure shows a SUZAKU X-ray image of one of the HESS sources, J1809-193. Supernova remnants and pulsar wind nebulae are candidates of these HESS sources. In fact, near J1809-193, there is a known pulsar and the ASCA observation revealed diffuse X-ray emission being consistent with a pulsar wind nebula (Bamba et al. 2003). The SUZAKU observation has furthermore confirmed this scenario. This data analysis was done by Anada et al. (2010) as a part of his PhD thesis. The mystery will be unveiled by further observations and theoretical considerations. In any cases, these sources would be the most energetic accelerators of cosmic rays in our Galaxy.

Takayuki TAMURA (ISAS/JAXA)

February 2011