Detection of the Extended γ -Ray Emission around Supernova Remnant DA 530 with Fermi-LAT.

We report the extended GeV γ -ray emission around the high Galactic latitude supernova remnant DA 530 with the PASS 8 data recorded by the Fermi Large Area Telescope. The γ -ray spectrum in the energy range of 100 MeV–1 TeV follows a power-law model with an index of 2.23. The γ -ray emission, which is much more extended than the radio shell of DA 530, and the spatial coincidence with the molecular cloud suggest that the γ -ray emission could be originated from the hadronic process, where the high-energy protons accelerated in and escaped from the shock of DA 530. With a steady-state injection model of protons, the γ -ray spectrum can be well fitted with the typical Galactic value for the diffusion coefficient and the low-energy content of the total escaped protons. [ABSTRACT FROM AUTHOR]