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GCN Circular 24293

Subject
GRB 190427A: Fermi GBM detection
Date
2019-04-27T17:14:36Z (5 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
C. Malacaria (NASA-MSFC/USRA), A. von Kienlin (MPE) 
and C. Meegan (UAH) report on behalf of the Fermi GBM Team:

"At 04:34:15.08  UT on 27 04 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190427A (trigger 578032460 / 190427190).
The event was also detected by the Swift/BAT
(Tohuvavohu et al. 2019, GCN 24261)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time 
is 106 degrees.

The GBM light curve consists of a dominant pulse with following 
structure and a duration (T90) of about 0.37 s (50-300 keV).
The time-averaged spectrum from T0-0.064 s to T0+0.384 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.05 +/- 0.18 and
the cutoff energy, parameterized as Epeak, is 246.40 +/- 78.20 keV.

The event fluence (10-1000 keV) in this time interval is
(4.855 +/- 0.717)E-07 erg/cm^2. The 64-msec peak photon flux measured
starting from T0+0.0 s in the 10-1000 keV band
is 18.8 +/- 1.1 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/
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