[vsnet-grb-info 25492] GRB 200416A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27592
SUBJECT: GRB 200416A: Fermi GBM observation
DATE:    20/04/16 13:41:38 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi at ba.infn.it>

E. Bissaldi (Politecnico and INFN Bari)
reports on behalf of the Fermi GBM Team:


"At 07:05:17.38 UT on 16 April 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 200416A (trigger 608713522 /200416295),
which was also detected by the Swift/BAT (Evans et al. 2020, GCN 27591).
The trigger was initially misclassified as a particle event by the flight software.
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 92 degrees.

The GBM light curve shows a double-peaked emission episode
with a duration (T90) of about 9 s (50-300 keV).
The time-averaged spectrum from T0-2 s to T0+6 s is
adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.87 +/- 0.15 and
the cutoff energy, parameterized as Epeak, is 74 +/- 6 keV.

The event fluence (10-1000 keV) in this time interval is
(1.43 +/-  0.08)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.064 s in the 10-1000 keV band
is 6.5 +/- 0.3 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 64 +/- 9 keV, alpha = -0.66 +/- 0.24
and beta = -2.5 +/- 0.3.


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/"