[vsnet-grb-info 19662] GRB 170803A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21406
SUBJECT: GRB 170803A: Fermi GBM observation
DATE:    17/08/03 23:03:54 GMT
FROM:    Peter Veres at UAH  <veresp at gmail.com>

P Veres and C Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 17:30:27.112 UT on 3 August 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170803A (trigger 523474232 / 170803729)
which was also detected by the Swift/BAT (LaPorte et al., GCN 21405).
The GBM on-ground location is consistent with the Swift position.


The angle from the Fermi LAT boresight at the GBM trigger time is 40 degrees.


The GBM light curve consists of a single pulse
with a duration (T90) of about 3.6 s (50-300 keV).
The time-averaged spectrum from T0-0.1 s to T0+2.2 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.71 +/- 0.12 and
the cutoff energy, parameterized as Epeak, is 154 +/- 13 keV.

The event fluence (10-1000 keV) in this time interval is
(1.65 +/- 0.076)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.1 s in the 10-1000 keV band
is 9.1 +/- 0.3 ph/s/cm^2.

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