{
  "bibcode": "2009GCN..9501....1G",
  "body": "S. Guiriec (UAH)\nreports on behalf of the Fermi GBM Team:\n\n\"At 18:35:56.49 UT on 31 May 2009, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 090531B (trigger 265487758 / 090531775)\nwhich was also detected by the SWIFT-BAT (Cummings et al. 2008, GCN 9461).\nThe GBM on-ground location is consistent with the Swift position.\n\nThe angle from the Fermi LAT boresight is 25 degrees.\n\nThe GBM light curve consists of a single peak with a duration (T90) of\nabout 2 s (8-1000 keV).\nThe time-averaged spectrum from T0-0.23 s to T0+0.77 s is\nadequately fit by a Band function with Epeak = 2166(+675-408) keV,\nalpha = -0.71(+0.10-0.10), and beta = -2.47(+0.25-0.46)\n(Castor C-Stat 780 for 602 d.o.f.).\n\nThe event fluence (8-1000 keV) in this time interval is\n(6.20 +/- 0.18)E-07 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0-0.23 s in the 8-1000 keV band is 1.49 +/- 0.04 ph/s/cm^2.\n\nThe spectral and temporal analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 9501,
  "createdOn": 1244596076000,
  "email": "sylvain.guiriec@lpta.in2p3.fr",
  "subject": "GRB 090531B: Fermi GBM detection",
  "submitter": "Sylvain Guiriec at UAH  <sylvain.guiriec@lpta.in2p3.fr>",
  "eventId": "GRB 090531B"
}