TITLE: GCN CIRCULAR NUMBER: 15128 SUBJECT: GRB 130828A: Fermi-LAT detection of a burst DATE: 13/08/29 03:25:30 GMT FROM: Giacomo Vianello at SLAC G.Vianello (Stanford), E.Sonbas (NASA/GSFC/Adiyaman Univ.) report on behalf of the Fermi-LAT team: At 07:20:00.15 on 2013-08-28 Fermi LAT detected high energy emission from GRB 130828A, which was also detected by Fermi-GBM (trigger 399367203). The best LAT on-ground location is found to be RA, DEC 259.83, +28.00 (J2000) with an error radius of 0.3 deg (68% containment, statistical error only), this was 40 deg from the LAT boresight at the time of the trigger, and triggered an autonomous repoint of the spacecraft. The data from the Fermi LAT show a significant increase (>> 5 sigma) in the event rate within 2.3 degree of the best HITL GBM location after the GBM trigger that is spatially and temporally correlated with the GBM emission with high significance. More than 30 photons above 100 MeV and 2 photons above 1 GeV are observed within 1000 seconds. The highest energy photon is a 1.5 GeV event which is observed 225 seconds after the GBM trigger. The Fermi LAT point of contact for this burst is Eda Sonbas (esonbas@slac.stanford.edu). The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.