2010 Volume 65 Issue 3 Pages 163-171
Fermi Gamma-ray Space Telescope (renamed from GLAST) has been observing the entire sky in the gamma-ray band with the Large Area Telescope (LAT) built by an international collaboration including Japan. In one year of the Science Operation since August 2008, many discoveries have been made in the gamma-ray band and importance of gamma-ray data in multi-wavelength analyses has been demonstrated. In this overview article, we describe selected science results already published: discoveries of pulsars bright in gamma-ray, accurate measurement on cosmic-ray electron spectrum, diffuse gamma-ray emission from the Milky Way galaxy, high-energy emission in gamma-ray bursts (GRBs), active galactic nuclei at cosmological distance and extra-galactic background gamma-ray radiation. The entire gamma-ray data and science analysis tools are available from Fermi Science Support Center at NASA: we wish the data be used widely in research and education.