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GCN Circular 15651

GRB 131229A: Fermi GBM detection
2014-01-02T20:50:44Z (10 years ago)
Narayana Bhat at U Alabama/Huntsville/GBM <>
A. von Kienlin (MPE) and P. N. Bhat (UAH)
report on behalf of the Fermi GBM Team:

"At 06:39:24.48 UT on 29 December 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 131229A (trigger 409991967 / 20131229277),
which was also detected by the Swift/BAT
(Page et al. 2013, GCN 15627 and Konus-Wind Golenetskii et al. 2013, GCN 15639).
The GBM on-ground location is consistent with the Swift/XRT position (Evans et al. 2013, GCN 15631) .

The angle from the Fermi LAT boresight is 84 degrees.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 13 s (50-300 keV).
The time-averaged spectrum from T0+0.002 s to T0+16.096 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.71 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 382.0 +/- 11.6 keV.

The event fluence (10-1000 keV) in this time interval is
(2.64 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+13.216 s in the 10-1000 keV band
is 24.0+/-0.4 ph/s/cm^2.

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