GCN Circular 32843
Arimoto M. (Kanazawa University) Pillera R. (Politecnico and INFN Bari), and Maheso D. (Johannesburg Univ.) report on behalf of the Fermi-LAT team: At 00:58:18.42 on October, 25, 2022 Fermi-LAT detected high-energy emission from GRB 221025A, GBM trigger 221025041 / 688352303 at 00:58:18.42 UT. The best LAT on-ground location is found to be RA, Dec = 133.4, 11.0 (J2000) with an error radius of 1.3 deg (90 % containment, statistical error only). This was 45 deg from the LAT boresight at the time of the trigger. The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance. The 100 MeV - 1 GeV photon flux in the time interval 0-200 s after the GBM trigger is (2.1 +/- 0.6)E-05 ph/cm2/s. The estimated integrated photon index above 100 MeV is -2.3 +/- 0.3. The highest-energy photon is a 1.3 GeV event with 93% probability which is observed 3 seconds after the GBM trigger. A Swift ToO has been requested for this burst. The Fermi-LAT point of contact for this burst is Dimakatso Jeannett Maheso (email@example.com). 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.