{
  "bibcode": "2009GCN..9446....1V",
  "body": "A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: \n\n\"At 04:09:01.14 UT on 28 May 2009, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 090528 (trigger 265176543 / 090528173).\nThe on-ground calculated location, using the GBM trigger \ndata, is RA = 134.9, DEC = -35.8 (J2000 degrees, \nequivalent to 09h 00m, -35d 48'), with an uncertainty \nof 3.4 degrees (radius, 1-sigma containment, \nstatistical only; there is additionally a systematic\nerror which is currently estimated to be 2 to 3 degrees).\nThe GBM on-ground location is within two sigma of the \nVela X-1 position, nevertheless we think this event \nis due to a real gamma-ray burst because intensity, duration \nand spectrum are unusual for Vela X-1 observed outburst.\n \nThe angle from the Fermi LAT boresight is 81 degrees.\n\nThe GBM light consists of one major structured pulse\nwith a duration (T90) of about 68 s (8-1000 keV). \nThe time-averaged spectrum from T0-5.120  s to T0+29.696 s is \nwell fit by a power law function with an exponential\nhigh energy cutoff.  The power law index is -1.7 +/- 0.1 and\nthe cutoff energy, parameterized as Epeak, is 99 +/- 26 keV\n(chi squared 357 for 359 d.o.f.).\n\nThe event fluence (8-1000 keV) in this time interval is \n(9.3 +/- 0.9)E-06 erg/cm^2. The 1-sec peak photon flux measured \nstarting from T0+3.072 s in the 8-1000 keV band \nis 7.6 +/- 0.3 ph/s/cm^2.\n\nThe spectral analysis results presented above are preliminary; \nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 9446,
  "createdOn": 1243697649000,
  "email": "azk@mpe.mpg.de",
  "subject": "GRB 090528: Fermi GBM detection",
  "submitter": "Andreas von Kienlin at MPE  <azk@mpe.mpg.de>",
  "eventId": "GRB 090528"
}