{
  "bibcode": "2021GCN.29781....1A",
  "body": "M. Arimoto (Kanazawa Univ.), M. Ohno (Hiroshima Univ. & Eotvos Univ.),\nF. Longo (University and INFN, Trieste) and M. Axelsson (KTH &\nStockholm Univ.) report on behalf of the Fermi-LAT team:\n\nOn April 10, 2021, Fermi-LAT detected high-energy emission from GRB\n210410A, which was also detected by Fermi-GBM (trigger 639708801 /\n210410037, Fermi GBM team, GCN 29777) and Swift/BAT&XRT (Kennea et al.\n2021, GCN 29778).\n\nThe best LAT on-ground location is found to be\nRA, Dec = 268.9, 45.2 (J2000)\nwith an error radius of 0.5 deg (90 % containment, statistical error\nonly). This position is consistent with the Swift/XRT localization.\nThis was 51 deg from the LAT boresight at the time of the GBM trigger:\nT0 = 00:53:16.5 UT.\n\nThe data from the Fermi-LAT show a significant increase in the event\nrate after the GBM trigger that is spatially and temporally correlated\nwith the GBM emission (2 degrees from the GBM location) with high\nsignificance.\n\nThe photon flux above 100 MeV in the time interval 0-300s after the\nGBM trigger is (4.0 +/- 0.7)e-05 ph/cm2/s, while the flux above 1 GeV\nis (1.3 +/- 0.7)e-06 ph/cm2/s.\n\nThe estimated photon index above 100 MeV is -2.5 +/- 0.2.\n\nThe highest-energy photon is a 4.2 GeV event which is observed 30\nseconds after the GBM trigger.\n\nThe Fermi-LAT point of contact for this burst is Masanori Ohno\n(ohno@astro.hiroshima-u.ac.jp).\n\nThe Fermi-LAT is a pair conversion telescope designed to cover the\nenergy band from 20 MeV to greater than 300 GeV. It is the product of\nan international collaboration between NASA and DOE in the U.S. and\nmany scientific institutions across France, Italy, Japan and Sweden.",
  "circularId": 29781,
  "createdOn": 1618043122000,
  "email": "arimoto@hp.phys.titech.ac.jp",
  "subject": "GRB 210410A: Fermi-LAT detection",
  "submitter": "Makoto Arimoto at Tokyo Inst of Tech  <arimoto@hp.phys.titech.ac.jp>",
  "eventId": "GRB 210410A"
}