GCN Circular 29771
Subject
GRB 210406A: Fermi GBM detection
Date
2021-04-07T15:39:56Z (4 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
C. Malacaria (NASA-MSFC/USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 17:11:30.57 UT on 06 April 2021, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 210406A (trigger 639421895 / 210406716),
which was also detected by the INTEGRAL/ISGRI (Mereghetti et al. 2021, GCN 29767).
The GBM on-ground location is consistent with the INTEGRAL position.
The angle from the Fermi LAT boresight at the GBM trigger time is 154 degrees.
The GBM light curve shows a long GRB with multiple spikes and
with a duration (T90) of about 17.4 s (50-300 keV).
The time-averaged spectrum from T0-2.0 s to T0+18.4 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.91 +/- 0.13 and
the cutoff energy, parameterized as Epeak, is 195.6 +/- 18.8 keV.
The event fluence (10-1000 keV) in this time interval is
(9.1 +/- 0.5)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+5.4 s in the 10-1000 keV band
is 4.6 +/- 0.6 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"