[vsnet-grb-info 10866] GRB 110818A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12287
SUBJECT: GRB 110818A: Fermi GBM observation
DATE:    11/08/19 23:02:20 GMT
FROM:    Shaolin Xiong at UAH  <sx0002 at 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."