Fermi-LAT Study of Gamma-ray Emission in the Direction of the Monoceros Loop Supernova Remnant

Diffusive acceleration by supernova shock waves can accelerate particles to very high energies (e.g. Blandford & Eichler 1987). Gamma-ray observations in GeV regimes are a powerful probe of these mechanisms. The Monoceros Loop (G205.5+0.5) is one of the most famous and well-studied middle-aged supernova remnants (SNRs). Its large diameter (∼ 3.8(°) ) makes it an ideal candidate for detailed morphological studies in GeV gamma rays since it is larger than the angular resolution of the Large Area Telescope (LAT) onboard the textit{Fermi Gamma-ray Space Telescope} above a few hundred MeV. The rim of the SNR in the south overlaps the Rosette nebula, which is a H _II region with molecular clouds. The interaction between these clouds and the SNR is suggested based on the broad and enhanced H_{alpha} line (Fountain et al. 1979). We present an analysis of the gamma-ray measurements by the LAT in the region of the SNR and the Rosette nebula.