TITLE: GCN CIRCULAR NUMBER: 35400 SUBJECT: GRB 231214B: Fermi GBM observation DATE: 23/12/19 08:42:25 GMT FROM: Elisabetta Bissaldi at Politecnico and INFN Bari <elisabetta.bissaldi@ba.infn.it> E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 07:53:55.52 UT on 14 December 2023, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 231214B (trigger 724233240 / 231214329), which was also detected by the Swift/BAT-GUANO (DeLaunay et al. 2023, GCN 35340). The on-ground calculated location, using the GBM trigger data, is RA = 137.9, DEC = -13.4 (J2000 degrees, equivalent to 09h 11m 36, -13d 24'), with a statistical uncertainty of 6.3 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ). The angle from the Fermi LAT boresight at the GBM trigger time is 78 degrees. The GBM light curve shows a single weak and structured emission episode with a duration (T90) of about 39 s (50-300 keV). The time-averaged spectrum from T0-2 s to T0+39 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is 0.30 +/- 0.19 and the cutoff energy, parameterized as Epeak, is 148 +/- 15 keV. The event fluence (10-1000 keV) in this time interval is (3.02 +/- 0.24)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0 in the 10-1000 keV band is 1.56 +/- 0.17 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/35400. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...