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The 2009 Fermi Symposium

Fermi-LAT Observations of LSI +61 303 and LS5039

Richard Dubois


The Fermi Gamma-ray Space Telescope has been observing the sky in gamma rays above 20 MeV since August 2008. The LAT (Large Area Telescope) wide field of view (>2sr) and large effective area combine to allow the entire sky to be scanned every 3 hours with unprecedented sensitivity and source localization in this energy range. This makes the LAT particularly suited to regular monitoring of the Galactic X-ray binary population. Results from the first year of observations of the bright sources LSI +61 303 and LS 5039, well observed binary systems at X-ray and TeV energies, will be presented. These sources are proving to be surprising in terms of spectral behavior and variability.