* Astronomy

Title: Observation of the TeV gamma-ray source MGRO J1908+06 with ARGO-YBJ
Authors: ARGO-YBJ Collaboration

The extended gamma ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for \sim 4 years by the ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parametrising the source shape with a two-dimensional Gauss function we estimate an extension \sigma = 0.49 ±0.22 degrees, consistent with a previous measurement by the Cherenkov Array H.E.S.S.. The observed energy spectrum is dN/dE = 6.1 ±1.4 x 10^-13 (E/4 TeV)^{-2.54 ±0.36} photons cm^-2 s^-1 TeV^-1, in the energy range \sim 1-20 TeV. The measured gamma ray flux is consistent with the results of the Milagro detector, but is \sim 2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ along 4 years of data taking support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity above 1 TeV \sim 1.8 times the Crab Nebula luminosity.

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