TITLE: GCN CIRCULAR NUMBER: 8246 SUBJECT: GRB 080916C: Fermi LAT observation DATE: 08/09/16 18:25:23 GMT FROM: Nicola Omodei at INFN(Pisa)/GLAST H. Tajima (SLAC), J. Bregeon (INFN Pisa), J. Chiang (SLAC), G. Thayer (SLAC) on behalf of the Fermi LAT team: We report a detection by the Fermi Large Area Telescope (LAT) of emission from the long GRB 080916C, which was triggered by the Fermi Gamma-ray Burst Monitor (GBM) at 00:12:45 UT on September 16th 2008 (GCN 8245). The angle of the GBM best position (RA, Dec=121.8,-61.3) with respect to the LAT boresight was 52 degrees at the time of the trigger, which is close the edge of our field of view. The data from the Fermi LAT shows a significant increase in the event rate within 10 degrees of the GBM location after the GBM trigger that is spatially and temporally correlated with the GBM emission with high significance. More than 10 photons are observed above 1 GeV during this time. The best LAT on-ground localization is found to be (RA,Dec=119.88, -56.59) with a 90% containment radius of 0.13 deg (statistical; 68% containment radius: 0.09 deg, preliminary systematic error is less than 0.1 deg) which is consistent with the GBM localization. This circular is an official product of the Fermi LAT team.