SCIENTIFIC RESULTS FROM THE FIRST 6 MONTHS OF THE FERMI/LAT MISSION

The Large Area Telescope (LAT), one of two instruments on the Fermi
Gamma-Ray Space Telescope (formerly GLAST, launched June 11, 2008) is a pair
conversion detector designed to study the gamma-ray sky in the energy
range 20 MeV to >300 GeV. The greatly improved sensitivity of the LAT
compared with its predecessor experiment, EGRET on the Compton Gamma-Ray
Observatory, coupled with the uniform and deep sky coverage, and lack of
consumables, provides a unique capability for studying the gamma-ray
Universe. A menagerie of gamma-ray sources exists: within our own Galaxy
pulsars, X-ray binaries, supernova remnants, and molecular clouds are a few
examples. The propagation of cosmic rays in the Galaxy produces diffuse
gamma-ray emission through interactions with the interstellar gas and
radiation fields, and is the bright background against which the sources are
detected. Diffuse gamma-ray emission is also expected from similar processes
in the solar system and nearby galaxies, such as the Large Magellanic
Cloud (which was detected by EGRET). The extragalactic gamma-ray sky is
dominated by emission from blazar active galactic nuclei which are highly
variable, and gamma-ray bursts, and perhaps exotic processes that may
contribute the to extragalactic gamma-ray background. The LAT has detected
many gamma-ray sources and the diffuse emissions of the Milky Way with
unprecedented sensitivity and resolution. I will give an overview of the
instrument and status, and results obtained on these topics for the first 6
months of the Fermi/LAT mission.