[vsnet-grb-info 17758] GRB 160314B: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19198
SUBJECT: GRB 160314B: Fermi GBM observation
DATE:    16/03/16 01:06:32 GMT
FROM:    C. Michelle Hui at MSFC/Fermi-GBM  <c.m.hui at nasa.gov>

C. M. Hui (NASA/MSFC) report on behalf of the Fermi GBM Team:

At 22:17:53.73 UT on 14 March 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160314B (trigger 479686677 / 160314929),
which was also detected by the LAT (G. Vianello et al., GCN 19197). 
GBM triggered on this GRB ~70s after exiting the SAA. 
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight at the GBM trigger time 
is 21 degrees.

The GBM light curve shows two peaks with a duration (T90) 
of about 100 s (50-300 keV). The time-averaged spectrum 
from T0-5.6 s to T0+18.9 s is best fit by a power law function 
with an exponential high-energy cutoff.  The power law index 
is -1.19 +/- 0.05 and the cutoff energy, parameterized as Epeak, 
is 954.5 +/- 274.0 keV.

The event fluence (10-1000 keV) in this time interval is
(8.98 +/- 0.34)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+8.4 s in the 8-1000 keV band
is 3.25 +/- 0.24 ph/s/cm^2.

A Band function fits the spectrum equally well with
Epeak = 848.9 +/- 368.0 keV, alpha = -1.20 +/- 0.06,
and beta = -1.86 +/- 0.22.

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