{
  "bibcode": "2013GCN.15591....1V",
  "body": "A. von Kienlin (MPE) and C. Meegan (UAH)\nreport on behalf of the Fermi GBM Team:\n\n\"At 13:07:56.97 UT on 09 December 2013, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 131209A (trigger 408287279 / 131209547),\nwhich was also detected by the Fermi/LAT(Vianello et al. 2013, GCN 15587),\nKonus-Wind (Golenetskii et al. 2013, GCN 15589) and INTEGRAL SPI-ACS. \nThe GBM on-ground location is consistent with the error box derived by\nthe intersection of the IPN annulus with the Fermi-LAT 1 sigma \nerror circle (Hurley et al. 2013, GCN 15588).\n\nThe GBM light curve shows a structured pulse\nwith a duration (T90) of about 14 s (50-300 keV).\nThe time-averaged spectrum from T0-2.560 s to T0+19.968 s is\nbest fit by a power law function with an exponential\nhigh-energy cutoff.  The power law index is -0.46 (+0.04/-0.04)  and\nthe cutoff energy, parameterized as Epeak, is 287 (+12/-11)keV\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.44 +/- 0.03)E-05 erg/cm^2. The 1.024-sec peak photon flux measured\nstarting from T0+11.328 s in the 10-1000 keV band\nis 8.0 +/- 0.3  ph/s/cm^2.\n\nA Band function fits the spectrum equally well with Epeak= 267 (+17/-14)\nkeV, \nalpha = -0.41 (+0.06/-0.05)  and beta = -2.79 (+0.24/-0.61).\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 15591,
  "createdOn": 1386764473000,
  "email": "azk@mpe.mpg.de",
  "subject": "GRB 131209A: Fermi GBM observation",
  "submitter": "Andreas von Kienlin at MPE  <azk@mpe.mpg.de>",
  "eventId": "GRB 131209A"
}