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GCN Circular 12801

GRB 120102A: Fermi GBM observation
2012-01-03T16:58:55Z (12 years ago)
Shaolin Xiong at UAH <>
S. Xiong (UAH)
reports on behalf of the Fermi GBM Team:

"At 02:16:23.24 UT on 02 Jan 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 120102A (trigger 347163385 / 120102095),
which was also detected by the Swift BAT/XRT/UVOT
(F. E. Marshall et al. 2012, GCN 12794)
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 84 degrees.

The GBM light curve consists of two main pulses
with a duration (T90) of about 17 s (50-300 keV).
The time-averaged spectrum from T0-1 s to T0+13 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.19 +/- 0.03 and
the cutoff energy, parameterized as Epeak, is 380 +/- 33 keV.
A Band function fits the spectrum equally well with
Epeak = 291 +/- 33 keV, alpha = -1.13 +/- 0.04, and beta = -2.14 +/- 0.13.

The event fluence (10-1000 keV) in this time interval is
(1.26 +/- 0.03)E-5 erg/cm^2. The 64 ms peak photon flux measured
starting from T0+4.8 s in the 10-1000 keV band
is 22.8 +/- 1.6 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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