{
  "bibcode": "2009GCN..9392....1V",
  "body": "A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: \n\n\"At 05:51:04.67 UT on 18 May 2009, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 090518B (trigger 264318666 / 090518244).\nThe on-ground calculated location, using the GBM trigger \ndata, is RA = 211.2, DEC = -16.7 (J2000 degrees, \nequivalent to 14h 05m, -16d 42'), with an uncertainty \nof 4.5 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 90 degrees.\n\nThe GBM light curve shows one structured peak\nwith a duration (T90) of about 12 s (8-1000 keV). \nThe time-averaged spectrum from T0-0.768 s to T0+6.656 s is \nwell fit by a power law function with an exponential\nhigh energy cutoff.  The power law index is -0.74 +/- 0.13 and\nthe cutoff energy, parameterized as Epeak, is 127 +/- 12 keV\n(chi squared 399 for 363 d.o.f.).\n\nThe event fluence (8-1000 keV) in this time interval is \n(2.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured \nstarting from T0-0.256 s in the 8-1000 keV band \nis 5.6 +/- 0.6 ph/s/cm^2.\n\nThe spectrum can also be fit by using a Band function with \nEpeak = 86 +/- 15 keV and beta = -2.10 +/- 0.14. However alpha \nis poorly constrained.\n\nThe spectral analysis results presented above are preliminary; \nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 9392,
  "createdOn": 1242657929000,
  "email": "azk@mpe.mpg.de",
  "subject": "GRB 090518B: Fermi GBM detection",
  "submitter": "Andreas von Kienlin at MPE  <azk@mpe.mpg.de>",
  "eventId": "GRB 090518B"
}