{
  "bibcode": "2015GCN.18041....1B",
  "body": "E. Bissaldi (INFN Bari), V. Connaughton (USRA) and\nA. von Kienlin (MPE) report on behalf of the Fermi GBM Team:\n\n\nAt 05:49:08.93 UT on 21 July 2015, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 150721A (trigger 459150552/150721242).\n\nThe on-ground calculated location, using the GBM trigger\ndata, is\n\nRA= 334.1, DEC = +7.8\n(J2000 degrees, equivalent to 22h 16m, 07d 48')\n\nwith an uncertainty of 1.5 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 trigger resulted in an Autonomous Repoint Request (ARR)\nby the GBM Flight Software owing to the high peak flux of the GRB.\nThis was accepted and the spacecraft slewed to the GBM in-flight\nlocation. The initial angle from the Fermi LAT boresight\nis 63 degrees.\n\nThis burst was also independently detected by INTEGRAL SPI-ACS.\n\nThe GBM light curve consists of a first peak at trigger\ntime followed by a very soft peak around 100 s.\nThe duration (T90) is about 20 s (50-300 keV).\nThe time-averaged spectrum from T0 to T0+20.2 s\nis best fit by a smoothly broken power law function.\nThe low-energy index is -0.58 +/- 0.06, the high-energy\nindex is -2.90 +/- 0.06 and the break energy\nis 45.7 +/- 2.3 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.52 +/- 0.08)E-05 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+5.4 s in the 10-1000 keV band\nis 16.7 +/- 0.3 ph/s/cm^2.\n\nA Band function fits the spectrum equally well\nwith Epeak = 56.26 +/- 1.15 keV,\nalpha = -0.16 +/- 0.07, and beta = -2.74 +/- 0.05.\n\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog.",
  "circularId": 18041,
  "createdOn": 1437512152000,
  "email": "Elisabetta.Bissaldi@uibk.ac.at",
  "subject": "GRB 150721A: Fermi GBM detection",
  "submitter": "Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>",
  "eventId": "GRB 150721A"
}