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GCN Circular 13339

GRB 120521B: Fermi GBM observation
2012-05-23T09:16:58Z (12 years ago)
David Gruber at MPE <>
David Gruber (MPE) reports on behalf of the Fermi GBM Team:

"At 09:07:52.39 UT on 21 May 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 120521B (trigger 359284074 / 120521380).
which was also detected by the Swift/BAT
(Krimm et al. 2012, GCN 13317)
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 a single pulse
with a duration (T90) of about 91 s (50-300 keV).
The time-averaged spectrum from T0-5 s to T0+29 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.34 +/- 0.20 and
the cutoff energy, parameterized as Epeak, is 213 +/- 29 keV

The event fluence (10-1000 keV) over the T90 time interval is
(3.11 +/- 0.07)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.4 s in the 10-1000 keV band
is 1.55 +/- 0.23 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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