GCN Circular 23227
Subject
GRB 180914A: Fermi GBM detection
Date
2018-09-14T23:47:15Z (6 years ago)
From
Suraj Poolakkil at UAH <sp0076@uah.edu>
S.Poolakkil(UAH), C. Meegan (UAH) and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:
"At 12:31:47.25 UT on 14 September 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180914A (trigger 558621112/ 180914522),
which was also detected by the Fermi LAT (E. Bissaldi et al. 2018, GCN
23225).
The GBM on-ground location is consistent with the LAT position.
The angle from the Fermi LAT boresight
at the GBM trigger time is 86 degrees.
The GBM light curve shows multiple peaks
with a duration (T90) of about 122.4 s (50-300 keV).
The time-averaged spectrum from T0+1.0 s to T0+156.7 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.70 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 296 +/- 7 keV.
The event fluence (10-1000 keV) in this time interval is
(9.152 +/- 0.128)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+21.37 s in the 10-1000 keV band
is 12.73 +/- 0.36 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."