Gamma-ray Burst 161020A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #20086
  S.Mereghetti (IASF-Milano), V. Savchenko (APC, Paris), D.Gotz (CEA, Saclay), C.Ferrigno (ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
  a gamma ray burst lasting about 15 s has been detected by IBAS in the IBIS/ISGRI data at 00:34:40 UT of 2016 October 20. This burst was also detected by Fermi/GBM (trigger num. 498616490).
  The burst occurred immediately after the end of a slew of the INTEGRAL satellite. For this reason the corresponding IBAS Alert was not distributed in real time.
  From an offline analysis we derived the burst coordinates (J2000):

  R.A.=  161.0309 deg
  DEC.=  -54.7687 deg
   

  with an uncertainty of about 2 arcmin (90% c.l.).
  The burst had a peak flux of 0.8 counts/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 4e-7 erg/cmq.
  A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html
• GCN Circular #20118
  C. M. Hui (NASA/MSFC), C Meegan (UAH), and P. Jenke (UAH) report on behalf of the Fermi GBM Team:
  At 00:34:46.95 UT on 20 October 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 161020A (trigger 498616490/161020024), which was also detected by INTEGRAL (Mereghetti et al., GCN 20086). The GBM on-ground location is consistent with the INTEGRAL position. The angle from the Fermi LAT boresight is 117 degrees.
  The GBM light curve shows a single peak with a duration (T90) of about 12.3 s (50-300 keV). The time-averaged spectrum from T0-6.1 s to T0+3.1 s is adequately fit by a simple power law function with index -1.74 +/- 0.05.
  The event fluence (10-1000 keV) in this time interval is (1.49 +/- 0.14)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.1s in the 10-1000 keV band is 2.3 +/- 0.2 ph/s/cm^2.
  The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog.