[vsnet-grb-info 18408] GRB 160824B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19856
SUBJECT: GRB 160824B: Fermi GBM detection
DATE:    16/08/25 02:27:41 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007 at uah.edu>

R. Hamburg (UAH)
reports on behalf of the Fermi GBM Team:

"At 14:21:12.94 UT on 24 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160824B (trigger 493741276 / 160824598).

The on-ground calculated location, using the GBM trigger
data, is RA = 73, DEC = +68, with an uncertainty
of 1 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 121
degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 3.6 s (50-300 keV).
The time-averaged spectrum from T0-0.26 to T0+3.07 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.20 +/- 0.06 and
the cutoff energy, parameterized as Epeak, is 649.70 +/- 32.60 keV.

The event fluence (10-1000 keV) in this time interval is
(1.39 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.7 s in the 10-1000 keV band
is 11.9 +/- 0.4 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."