//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19197 SUBJECT: GRB 160314B: Fermi-LAT detection DATE: 16/03/15 22:29:29 GMT FROM: Judith Racusin at GSFC G. Vianello (Stanford), J. Racusin (NASA/GSFC), D. Kocevski (NASA/GSFC), F. Longo (University of Trieste and INFN), and B. Ahlgren (KTH), report on behalf of the Fermi-LAT team: At 22:17:53.73 on March 14, 2016 Fermi-LAT detected high-energy emission from GRB 160314B, which was also detected by Fermi-GBM (trigger 479686676 / 160314929). The best LAT on-ground location is found to be: RA, Dec (J2000) = 167.56, 45.67 with an error radius of 0.65 deg (90 % containment, statistical error only). Unfortunately, the LAT was not taking data at the trigger time T0, because Fermi was just exiting the South Atlantic Anomaly (SAA). Note that LAT and GBM have slightly different SAA definitions in onboard software. However, LAT resumed data taking ~30 seconds after T0, and the GRB was 21 deg from the LAT boresight at that time. The LAT data show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance. The highest-energy photon is a 900 MeV event which is observed ~630 seconds after the GBM trigger. The Fermi-LAT point of contact for this burst is B. Ahlgren (bjornah@kth.se). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19198 SUBJECT: GRB 160314B: Fermi GBM observation DATE: 16/03/16 01:06:32 GMT FROM: C. Michelle Hui at MSFC/Fermi-GBM C. M. Hui (NASA/MSFC) report on behalf of the Fermi GBM Team: At 22:17:53.73 UT on 14 March 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160314B (trigger 479686677 / 160314929), which was also detected by the LAT (G. Vianello et al., GCN 19197). GBM triggered on this GRB ~70s after exiting the SAA. The GBM on-ground location is consistent with the LAT position. The angle from the Fermi LAT boresight at the GBM trigger time is 21 degrees. The GBM light curve shows two peaks with a duration (T90) of about 100 s (50-300 keV). The time-averaged spectrum from T0-5.6 s to T0+18.9 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.19 +/- 0.05 and the cutoff energy, parameterized as Epeak, is 954.5 +/- 274.0 keV. The event fluence (10-1000 keV) in this time interval is (8.98 +/- 0.34)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+8.4 s in the 8-1000 keV band is 3.25 +/- 0.24 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak = 848.9 +/- 368.0 keV, alpha = -1.20 +/- 0.06, and beta = -1.86 +/- 0.22. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog.