{
  "bibcode": "2022GCN.31896....1B",
  "body": "E. Bissaldi (Politecnico and INFN Bari), M. Arimoto (Kanazawa Univ.),\nS. Ciprini (INFN and ASI), F. Giacchino (INFN Roma Tor Vergata and ASI),\nM. Giroletti (INAF/IRA Bologna), and L. Scotton (CNRS/IN2P3/LUPM)\nreport on behalf of the Fermi-LAT team:\n\n\n\"On April 8, 2022, Fermi-LAT detected high-energy emission from GRB 220408B,\nwhich was also detected by Fermi-GBM (trigger 671095689 / 220408311, GCN 31854),\nAstroSat CZTI (Gopalakrishnan et al. 2022, GCN 31863) and was reported by the IPN\n(Kozyrev et al. 2022. GCN 31878).\n\nThe best LAT on-ground location is found to be\n\nRA, Dec = 92.48, -50.97 (degrees, J2000)\n\nwith an error radius of 0.06 deg (90 % containment, statistical error only).\nThis was 30 deg from the LAT boresight at the time of the GBM trigger:\n\nT0 = 07:28:04.65 UT.\n\nThe data from the Fermi-LAT show a significant increase in the event rate\nthat is spatially and temporally correlated with the GBM emission\nwith high significance.\nThe photon flux above 100 MeV in the time interval 0-2500s\nafter the GBM trigger is (2.0 +/- 0.5)E-06 ph/cm2/s.\n\nThe estimated photon index above 100 MeV is -1.9 +/- 0.2.\n\nThe highest-energy photon is a 22 GeV event\nwhich is observed 42 seconds after the GBM trigger.\n\n\nThe Fermi-LAT point of contact for this burst is\nElisabetta Bissaldi (elisabetta.bissaldi@ba.infn.it).\n\n\nThe Fermi-LAT is a pair conversion telescope designed to cover the energy band\nfrom 20 MeV to greater than 300 GeV. It is the product of an international\ncollaboration between NASA and DOE in the U.S. and many scientific institutions\nacross France, Italy, Japan and Sweden.\"",
  "circularId": 31896,
  "createdOn": 1649864964000,
  "email": "elisabetta.bissaldi@ba.infn.it",
  "subject": "GRB 220408B: Fermi-LAT detection",
  "submitter": "Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>",
  "eventId": "GRB 220408B"
}