GCN Circular 12133
Subject
GRB 110709A: Fermi GBM observation
Date
2011-07-10T03:12:50Z (13 years ago)
From
Valerie Connaughton at UAH/NSSTC <valerie.connaughton@nasa.gov>
V. Connaughton (UAH) reports on behalf of the Fermi GBM Team:
"At 15:24:27.37 UT on 09 July 2011, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 110709A (trigger 331917869 / 110709642),
which was also detected by the Swift/BAT (Holland et al. 2011,
GCN 12118) and the Swift/XRT (Evans et al. 2011, GCN 12119).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at trigger time was 54 degrees.
Approximately 6 - 200 s from trigger time, the Fermi spacecraft executed
an automatic maneuver in response to a command from GBM, in
order to place the burst closer to the LAT boresight, and observed
this position for the following 2.5 hours, subject to Earth limb
constraints.
The GBM light curve shows several bright peaks from trigger time
to 50-s post-trigger, with a duration (t90) of 43.5 s (50-300 keV).
The time-averaged spectrum from T0-4.096 s to T0+62.5 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.16 +/- 0.02 and
the cutoff energy, parametrized as Epeak, is 533 +/- 37 keV.
The event fluence (10-1000 keV) in this time interval is
(4.43 +/- 0.07)E-5 erg/cm^2. The 64 ms peak photon flux measured
starting from T0+25.28 s in the 10-1000 keV band
is 15.4 +/- 1.7 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."