Detection of Gamma-Ray Emission in the Region of the Supernova Remnants G296.5+10.0 and G166.0+4.3

Abstract

52 months of accumulated observations by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope in the region of the supernova remnants G296.5+10.0 (PKS 1209-51/52) and G166.0+4.3 (VRO 42.05.01) are analyzed. GeV emission is detected coincident with the position of the sources at the 5-sigma and 11-sigma levels above the background, respectively, for the best-fit spectral and spatial scenarios. The gamma-ray spectrum of the sources can be described with a power-law in energy. G166.0+4.3 shows a soft GeV spectrum while that of G296.5+10.0 is flat (in the "nu-Fnu" representation). The origin of the gamma-ray emission from the sources is explored. Both leptonic and hadronic mechanisms can account for the high-energy emission from G296.5+10.0, while a leptonic scenario is preferred for G166.0+4.3.