[vsnet-grb-info 20798] GRB 180703A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22896
SUBJECT: GRB 180703A: Fermi GBM detection
DATE:    18/07/04 16:59:58 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076 at uah.edu>

S.Poolakkil and C. Meegan (both UAH) report on
behalf of the Fermi GBM Team:

"At 21:01:40.50 UT on 03 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180703A (trigger 552344505 / 180703876),
which was also detected by the Fermi LAT (Racusin et al. 2018, GCN 22883).
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 44 degrees.

The GBM light curve shows a single peak
with a duration (T90) of about 20.2 s (50-300 keV).
The time-averaged spectrum from T0-3.1 s to T0+25.6 s is
best fit by a Band function with Epeak = 360 +/- 33 keV,
alpha = -0.80 +/- 0.04 and beta = -1.95 +/- 0.08.

The event fluence (10-1000 keV) in this time interval is
(2.001 +/- 0.043)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.52 s in the 10-1000 keV band
is 11.1 +/- 0.25 ph/s/cm^2.

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