[vsnet-grb-info 18306] GRB 160802A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19754
SUBJECT: GRB 160802A: Fermi GBM detection
DATE:    16/08/02 13:08:10 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi at uibk.ac.at>

E. Bissaldi (Politecnico & INFN Bari)
reports on behalf of the Fermi GBM Team:


"At 06:13:29.63 UT on 02 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160802A (trigger 491811213 / 160802259).
The on-ground calculated location, using the GBM trigger data, is

RA, Dec =  35.29, +72.69

(J2000 degrees, equivalent to 02h 21m, 72d 41'),
with an uncertainty of 1 degree (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 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 106 degrees.

The GBM light curve consists of 2 FRED-like peaks
with a duration (T90) of about 16.4 s (50-300 keV).
The time-averaged spectrum from T0-0.3 s to T0+19.4 s is
best fit by a Band function with Epeak = 284 +/- 7 keV,
alpha = -0.71 +/- 0.02, and beta = -2.44 +/- 0.06.

The event fluence (10-1000 keV) in this time interval is
(1.04 +/- 0.08)E-04 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.7 s in the 10-1000 keV band
is 72.5 +/- 0.7 ph/s/cm^2.


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