TITLE:   GCN CIRCULAR
NUMBER:  19555
SUBJECT: GRB 160623A: Fermi GBM detection/observation
DATE:    16/06/23 19:10:15 GMT
FROM:    Bagrat Mailyan at UAH  <bm0054@uah.edu>

B. Mailyan (UAH), K. Toelge (MPE) and O. Roberts (UCD)
report on behalf of the Fermi GBM Team:

"At 05:00:34.23 UT on 23 June 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160623A (trigger 488350838 / 160623209 ),
which was also detected by the LAT (G. Vianello et al. 2016, GCN 19553)
and Konus-Wind (D. Frederiks et al. 2016, GCN 19554).
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight at the GBM trigger time is 83
degrees.

The GRB was occulted by the Earth for a large part of its duration, and
the GBM trigger occurred ~50 s after the start of the GRB based on
the Konus-Wind lightcurve.
The GBM light curve consists of a single peak with a duration of about 50 s.
The time-averaged spectrum from T0-4.9 s to T0+32.8 s is
best fit by a power law function.  The power law index is -1.60 +/- 0.04.

The event fluence (10-1000 keV) in this time interval is
(5.598 +/- 0.369)E-06 erg/cm^2.

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