{
  "bibcode": "2009GCN..9295....1B",
  "body": "Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team:\n\n\n\"At 13:15:11.06 UT on 28 April 2009, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 090428B (trigger 262617313 / 090428552).\nThe on-ground calculated location, using the GBM trigger\ndata, is RA = 0.8, DEC = +6.5 (J2000 degrees,\nequivalent to 00h 03m, 06d 30'), with an uncertainty\nof 4.4 degrees (radius, 1-sigma containment,\nstatistical only; there is additionally a systematic\nerror which is currently estimated to be 2 to 3 degrees).\n\nThe angle from the Fermi LAT boresight is 101 degrees.\n\nThe GBM light curve consists of a broad single peak\nwith a duration (T90) of about 30 s (8-1000 keV).\nThe time-averaged spectrum from T0-9.2 s to T0+15.3 s is\nadequately fit by a power law function with an exponential\nhigh energy cutoff. The power law index is -1.86 +/- 0.07\nand the cutoff energy, parameterized as Epeak,\nis 65 +/- 16 keV (chi squared 279 for 241 d.o.f.).\n\nThe event fluence (8-1000 keV) in this time interval is\n(5.2 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+3.1 s in the 8-1000 keV band\nis 10.1 +/- 0.7 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\n(chi squared 278 for 240 d.o.f.) with Epeak = 53 +/- 19 keV,\nalpha = -1.81 +/- 0.13 and beta = -2.17 +/- 0.21.\n\n\nThe spectral analysis results presented above are preliminary; \nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 9295,
  "createdOn": 1241018556000,
  "email": "ebs@mpe.mpg.de",
  "subject": "GRB 090428B: Fermi GBM detection",
  "submitter": "Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>",
  "eventId": "GRB 090428B"
}