{
  "bibcode": "2017GCN.22112....1H",
  "body": "R. Hamburg (UAH) and C. Meegan (UAH)\nreport on behalf of the Fermi GBM Team:\n\n\"At 15:44:46.50 UT on 8 November 2017, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 171108A (trigger 531848691 / 171108656).\nThe on-ground calculated location, using the GBM trigger\ndata, is RA = 115.0, DEC = +39.8 (J2000 degrees,\nequivalent to 07 h 40 m, 39 d 48'), with an uncertainty\nof 4.7 degrees (radius, 1-sigma containment,\nstatistical only; there is additionally a systematic\nerror which we have characterized as a core-plus-tail model, with 90% of\nGRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg\nsystematic error. [Connaughton et al. 2015, ApJS, 216, 32]).\n\nAlthough this GRB is soft in nature, the trigger resulted in an\nAutonomous Repoint Request (ARR) by the GBM Flight Software\nowing to high peak flux in the background before trigger time.\nThis ARR was accepted and the spacecraft slewed to the GBM in-flight\nlocation. The initial angle from the Fermi LAT boresight to\nthe best GBM ground location is 84 degrees.\n\nThe GBM light curve shows a bright peak\nwith a duration (T90) of about 0.03 s (50-300 keV).\nThe time-averaged spectrum from T0-0.064 s to T0+0.064 s is\nadequately fit by a power law function with an exponential\nhigh-energy cutoff and a blackbody. The power law index is -1.6 +/- 0.4,\nthe cutoff energy, parameterized as Epeak, is 47 +/- 28 keV,\nand the temperature is 18.0 +/- 3.0 kT.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.0 +/- 0.1)E-05 erg/cm^2. The 0.064-sec peak photon flux measured\nstarting from T0-0.064 s in the 10-1000 keV band\nis 687 +/- 166 ph/s/cm^2.\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 22112,
  "createdOn": 1510206073000,
  "email": "rkh0007@uah.edu",
  "subject": "GRB 171108A: Fermi GBM detection",
  "submitter": "Rachel Hamburg at UAH  <rkh0007@uah.edu>",
  "eventId": "GRB 171108A"
}