GCN Circular 12287
Subject
GRB 110818A: Fermi GBM observation
Date
2011-08-19T23:02:20Z (13 years ago)
From
Shaolin Xiong at UAH <sx0002@uah.edu>
S. Xiong (UAH) reports on behalf of the Fermi GBM Team:
"At 20:37:54.221 UT on 18 August 2011, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 110818A (trigger 335392676 / 110818860 ),
which was also detected by the Swift (Markwardt et al. 2011, GCN 12279).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 96 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of multiple peaks
with a duration (T90) of about 75 s (50-300 keV).
The time-averaged spectrum from T0-16.4 s to T0+57.3 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.33 +/- 0.08 and
the cutoff energy, parameterized as Epeak, is 256.3 +/- 55.3 keV.
The event fluence (10-1000 keV) in this time interval is
(8.2 +/- 0.6)E-6 erg/cm^2. The 64 ms peak photon flux measured
starting from T0+22.66 s in the 10-1000 keV band
is 5.0 +/- 1.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."