//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19826 SUBJECT: GRB 160819A: Fermi GBM detection DATE: 16/08/20 03:32:34 GMT FROM: Peter Veres at UAH P Veres (UAH) and C Meegan (UAH) report on behalf of the Fermi GBM Team: "At 20:27:35.49 UT on 19 August 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160819A (trigger 493331259 / 160819852). The on-ground calculated location, using the GBM trigger data, is RA = 118.91, DEC = -20.64 (J2000 degrees, equivalent to 7 h 56 m, -20 d 38 '), with an uncertainty of 1.13 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] ). This burst was also independently detected by INTEGRAL SPI-ACS. The trigger resulted in an Autonomous Repoint Request (ARR) by the GBM Flight Software owing to the high peak flux of the GRB. This ARR was accepted and the spacecraft slewed to the GBM in-flight location. The initial angle from the Fermi LAT boresight to the GBM ground location is 66 degrees. The GBM light curve consists of multiple overlapping pulses with a duration (T90) of about 23.8 s (50-300 keV). The time-averaged spectrum from T0+18.4s to T0+41 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.45 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 109.9 +/- 5.4 keV. The event fluence (10-1000 keV) in this time interval is (2.14+/- 0.05)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+28.9 s in the 10-1000 keV band is 17.1 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19827 SUBJECT: BAT detection and localization of GRB 160819A DATE: 16/08/20 23:08:58 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift Team: At 20:27:30.40 UT on 2016-08-19, the Swift Burst Alert Telescope (BAT) detected GRB 160819A, which was also detected by Fermi/GBM and INTEGRAL SPI-ACS (Veres et al., GCN Circ. 19826). BAT was slewing to a pre-planned target at that time, so it did not trigger on the burst. However, ground analysis using the slew data fromT+27 to T+106 sec reveals the GRB location of RA, Dec = 114.139, -22.347 deg, which is RA(J2000) = 07h 36m 33.3s Dec(J2000) = -22d -20' -50.2" with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment). This position is 4.76 deg from the one reported by Fermi GBM, which is consistent with the reported GBM error circle (Veres et al., GCN Circ. 19826). The mask-weighted light curve shows a double-peaked structure that starts before the beginning of the available event data, and ends at ~ T+70 s. The two peaks occur at ~T+47 s and ~T+53 s, respectively. The time-averaged spectrum from T+26.6 to T+73.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.70 +- 0.05. The fluence in the 15-150 keV band is (7.76 +/- 0.23) x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+46.70 sec in the 15-150 keV band is 12.1 +- 0.6 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/00086022006/BA/