[vsnet-grb-info 17674] GRB 160227B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19111
SUBJECT: GRB 160227B: Fermi GBM detection
DATE:    16/02/28 20:58:28 GMT
FROM:    Matthew Stanbro at UAH/Fermi  <mcs0001 at uah.edu>

Matthew Stanbro (UAH) and C. Meegan (UAH)
reports on behalf of the Fermi GBM Team:

"At 19:57:06.33 UT on 27 February 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160227B (trigger 478295830 / 160227831).

The on-ground calculated location, using the GBM trigger
data, is RA = 123.4, DEC = -48.3, with an uncertainty
of 1.3 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 54
degrees.

The GBM light curve consists of 2 episodes
with a duration (T90) of about 8 s (50-300 keV).
The time-averaged spectrum from T0+0.14 s to T0+8.34 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.25 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 544 +/- 19 keV

The event fluence (10-1000 keV) in this time interval is
(1.86 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.73 s in the 10-1000 keV band
is 10.27 +/- 0.27 ph/s/cm^2.

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