{
  "bibcode": "2012GCN.12989....1V",
  "body": "V. Vasileiou (CNRS/IN2P3/LUPM) and J. L. Racusin (NASA/GSFC) report on behalf of\nthe Fermi-LAT team:\n\nFermi-LAT has detected high energy emission from GRB 120226A in ground analysis.\nThe GRB was triggered on by Fermi-GBM at 20:54:17.03 on Febuary 26, 2012\n(trigger 351982459).\n\nThe GRB was significantly detected during the prompt phase only using a\nnon-standard LAT data selection most sensitive in the tens-of-MeV energy range,\nwith which over ~50 counts above background were detected within a 60 s interval\ncoinciding with the time of the GBM emission. This data selection has\ninsufficient spatial resolution to provide a reliable LAT localization.\n\nHowever, the GRB became detectable with the standard LAT analysis techniques\nonly after data of longer time scales were accumulated. A preliminary\nmaximum-likelihood analysis of the E>100MeV P7SOURCE_V6 LAT data generated\nduring the first 1.9 ks after the GBM trigger (until the GRB became occulted by\nthe Earth) revealed a source with a ~4 sigma statistical significance,\ncorresponding to ~14 excess events. The source spectrum is best fit with a power\nlaw of index -1.6+-0.3. Using this analysis, we obtained the best LAT on-ground\nlocalization of:\nRA(J2000) = 305.30 deg\nDec(J2000) = 40.75 deg\nwith an error radius 0.36 deg (90% containment, statistical error only), which\nis 4 deg from the best GBM localization and ~37 deg with respect to the LAT\nboresight at the time of the trigger. The GRB triggered an autonomous repoint of\nthe Fermi spacecraft bringing our best localization to ~12 deg from the LAT\nboresight for 1.9 ks after the trigger. The burst position is close to the\nGalactic plane at (l,b) = 78.5, 2.3 deg.\n\nA Swift TOO has been requested.\n\nThe Fermi LAT point of contact for this burst is Vlasios Vasileiou\n(vlasios.vasileiou@lupm.in2p3.fr).\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": 12989,
  "createdOn": 1330350787000,
  "email": "Vlasios.Vasileiou@lupm.in2p3.fr",
  "subject": "GRB 120226A: Fermi-LAT detection of a burst",
  "submitter": "Vlasios Vasileiou at LUPM/Fermi-LAT  <Vlasios.Vasileiou@lupm.in2p3.fr>",
  "eventId": "GRB 120226A"
}