Preliminary Evidence for TeV Gamma Ray Emission from the Galactic Plane using the Milagro Detector

The majority of galactic gamma rays are produced by interaction of cosmic rays with matter or radiation fields. This results in a diffuse radiation concentrated in the galactic plane where the flux of cosmic rays and the density of material (mostly atomic, molecular and ionized hydrogen) is high. The interactions producing gamma rays include the decay of π produced in spallation reactions and inverse Compton scattering of electrons on cosmic microwave background. Milagro is a water Cherenkov extensive air shower array capable of continuously viewing the entire overhead sky and is sensitive to gamma rays with energies below 1 TeV. The combination of a large duty factor and a large field of view results in a higher sensitivity to the diffuse emission from the galaxy compared to previous experiments in the same energy band. Preliminary evidence for TeV gamma emission from the galactic plane using Milagro data will be presented at the conference.