TITLE: GCN CIRCULAR NUMBER: 14971 SUBJECT: GRB 130702A / Fermi394416326 : Fermi-LAT detection of a burst DATE: 13/07/03 17:34:28 GMT FROM: Giacomo Vianello at SLAC T. Cheung (NRL), G.Vianello (Stanford), S. Zhu (NASA/GSFC), J. Racusin (NASA/GSFC), V. Connaughton (UAH) and B. Carpenter (NASA/GSFC) report on behalf of the Fermi-LAT team: At 00:05:23.079 UTC on July 02, 2013, Fermi GBM triggered on GRB 130702A / Fermi394416326 (trigger 394416326). The LAT detected high energy emission from this GRB, which was also detected in the optical band by iPTF (Singer et al., GCN 14967) and confirmed by FTN (Guidorzi et al., GCN 14968). The best LAT on-ground location is found to be: RA, DEC = 216.4, 15.8 (J2000), with an error radius of 0.5 deg (90% containment, statistical error only) This position is 4 deg from the best GBM position (RA, Dec = 218.81, +12.25 with a 4 deg radius), and 0.8 deg from the position of the optical afterglow. A preliminary IPN triangulation of the burst using GBM and Konus-Wind data gives an annulus with center RA, DEC = 260.8992, -20.7746 (J2000) of radius 50.85 degrees and a width of (-32.73,+18.42) deg (3 sigma). The center of this annulus is 6.05 deg (0.99 sigma) from the LAT location (Private Communication, with possible IPN refinements using data from distant spacecraft). The best LAT localization for the source was ~75 deg from the LAT boresight at the time of the trigger, i.e., outside the nominal field of view of the LAT (~65 deg), but it entered the FOV at T0+250 s to exit again at T0 + 2200 s. The data from the Fermi LAT in such time interval show a significant increase in the event rate within 10 degree of the source location, with a significance of more than 5 sigmas. This analysis has been carried out with the P7SOURCE_V6 class. More than 5 photons above 100 MeV are observed within 2200 seconds. The highest energy photon is a 1.5 GeV event which is observed 260 seconds after the GBM trigger. The Fermi LAT point of contact for this burst is Giacomo Vianello (giacomov@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.