An X-ray Gas Associated with the Galactic Center Radio Arc

The Galactic center region near 0.2deg hosts a mixture of nonthermal linear filaments and thermal radio continuum features associated with the radio Arc. Chandra observations of this region find an X-ray filament and thermal X-ray gas with an extent of roughly 60''x2'' and 5'x3', respectively. The X-ray filament lies at the edge of the nonthermal radio filaments and a dense molecular shell G0.11-0.11. Diffuse X-ray gas from the molecular shell is fitted either by two-temperature (1 and 10 keV) thermal X-ray gas or by power-law and 1 keV thermal gas. A fluorescent 6.4 keV line emission has also been detected throughout the molecular shell. This cloud coincides within the error circle of a steady high energy >=100 MeV source 3EGJ1746-2851 with a photon index α ~1.7. These observations show the strongest evidence for the interaction of a molecular cloud with nonthermal radio filaments and suggest that the expansion of the molecular shell into the radio filaments of the Arc has led to the acceleration of high energy electrons at the interface between nonthermal radio filaments of the Arc and the dense molecular cloud G0.11-0.11.