GCN Circular 10702
Subject
GRB 100427A: Fermi GBM detection
Date
2010-04-29T00:31:46Z (15 years ago)
From
Adam Goldstein at Fermi-GBM/UAH <adam.m.goldstein@msfc.nasa.gov>
A. Goldstein (UAH) and D. Gruber (MPE)
report on behalf of the Fermi GBM Team:
"At 08:32:08.71 UT on 27 April 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100427A (trigger 294049930 / 100427356),
which was also detected by the Swift-BAT (J.R. Cummings et al. 2010,
GCN 10699). The GBM on-ground location is consistent with the Swift-BAT
position. The angle from the Fermi LAT boresight is 29 degrees.
The GBM light curve consists of a single pulse with multiple peaks
with a duration (T90) of about 24 s (8-1000 keV).
The time-averaged spectrum from T0-4.1 s to T0+11.3 s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -1.02 +0.12/-0.11 and
the cutoff energy, parameterized as Epeak, is 121.0 +15.4/-11.8 keV
(Castor C-Stat 519 for 484 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(3.01 +/- 0.13)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+5.18 s in the 8-1000 keV band
is 4.79 +/- 0.24 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."