Observation of the gamma ray source MGRO J1908+06 with ARGO-YBJ

The gamma ray source MGRO J1908+06 has been observed for 3 years by the ARGO-YBJ experiment at energies above ~1 TeV. According to our data the source is extended, and parametrizing the shape with a two???dimensional Gaussian we estimate an extension sigma_ext = (0.50+-0.35) deg. The large size of the emitting region supports the identification of the source as the Wind Nebula associated with the Fermi pulsar PSR J1907+0602. The energy spectrum obtained is dN/dE = 2.2+-0.4 x 10^(-13) (E/7 TeV)^(-2.3+-0.3) photons cm-2 s-1 TeV-1, in the range ~2-30 TeV. The flux is in good agreement with the results of the Milagro detector, but is ~3 times larger than what has been obtained by the Cherenkov Array H.E.S.S.. The origin of these disagreements remains unclear, but it could be due to a complex morphology of the source and/or to the contribution of the diffuse gamma ray flux from the Galactic plane.