Post-launch Performance of the Fermi Large Area Telescope

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope started nominal operations on August 11, 2008, after a successful launch and commissioning phase. The LAT photon data have been first released to the public on August 25, 2009. The LAT is currently performing an all-sky gamma-ray survey with unprecedented sensitivity and angular resolution.

The LAT pre-launch response was tuned using MonteCarlo simulations and data from a beam test campaign. During the first year of nominal operation, a major effort was devoted to the detailed study of the in-flight detector performance. This poster will describe the main features of the so-called Pass6_version3 analysis, which has been optimized for the study of point-like sources and the production of the LAT catalog. This analysis represents our current understanding of the instrument and was the official framework applied to the first-year public data release.

We will also present some of the ongoing efforts to improve our description of the detector response and to maximize its performance.