TITLE: GCN CIRCULAR NUMBER: 17094 SUBJECT: GRB 141118A: Fermi GBM Detection DATE: 14/11/24 17:54:58 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM Team: "At 16:15:50.31 on November 18 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 141118A (trigger 438020153/141118678). The GBM on-ground location, using the Fermi GBM trigger data, is RA = 158.1, Dec = 19.8 (J2000 degrees, equivalent to 10h 32m 24s, 19d 48'), with an uncertainty of 2.2 degrees (radius, 1-sigma containment,statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). GBM's location is consistent with the IPN Triangulation (K. Hurley et al. 2014, GCN 17073). This GRB was also detected by Konus-Wind (Golenetskii et al. GCN 17074). A follow-up search of GBM's error box by iPTF produced an optical candidate, well within the GBM 1 sigma confidence region, that on further investigations turned out to be a fading SNe unrelated to the GRB (Singer et al. 2014, GCN 17079). The angle of the burst direction to the Fermi LAT boresight is 74 degrees. The GBM light curve consists of a single peak with a duration (T90) of about 4.4 s (50-300 keV). The time-averaged spectrum from T0-2.9 s to T0+3.2s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.77 +/- 0.09 and the cutoff energy, parameterized as Epeak, is 286 +/- 34 keV. The event fluence (10-1000 keV) in this time interval is (3.3 +/- 0.2)E-06 erg/cm^2. The 1 sec peak photon flux measured starting from T0+0.0 s in the 10-1000 keV band is 6.5 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."