TITLE:   GCN CIRCULAR
NUMBER:  18628
SUBJECT: GRB 151120A: Fermi GBM observation
DATE:    15/11/20 15:43:09 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE)reports on behalf of the Fermi GBM Team:

"At 08:22:53.70 UT on 20 November 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 151120A (trigger 469700577 / 151120349),
which was also detected by the INTEGRAL/ISGRI (Mereghetti et al. 2015, GCN
18623)
The GBM on-ground location is consistent with the INTEGRAL position.

The angle from the Fermi LAT boresight at the GBM trigger time is 65.6
degrees.

The GBM light curve consists of multiple peaks 
with a duration (T90) of about 20 s (50-300 keV).
The time-averaged spectrum from T0+0.003 s to T0+21.760 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.29 +/- 0.03 
and the cutoff energy, parameterized as Epeak, is 243 (+23/-19)keV.

The event fluence (10-1000 keV) in this time interval is
(9.4 +/- 0.3)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+11.9682 s in the 10-1000 keV band
is 7.0 +/- 0.3 ph/s/cm^2.

A Band function fits the spectrum equally well with 
Epeak = 217 (+27/-25) keV, alpha = -1.26 +/- 0.04  
and beta = -2.30 (+0.20/-0.40). 

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