TITLE:   GCN CIRCULAR
NUMBER:  28019
SUBJECT: GRB 200623A: Fermi GBM observation
DATE:    20/06/23 21:46:47 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 03:18:00.64 UT on 23 June 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 200623A (trigger 614575085 / 200623138)
which was also detected by the Swift/BAT-GUANO (DeLaunay et al., GCN 28013).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 36
degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 0.6 s (50-300 keV).
The time-averaged spectrum from T0-64 ms to T0 is
best fit by a simple power law function with index -1.09 +/- 0.09.


The event fluence (10-1000 keV) in this time interval is
(5.2 +/- 0.6)E-7 erg/cm^2. The 64-ms peak photon flux measured
starting from T0-64 ms in the 10-1000 keV band
is 4.7 +/- 1.0 ph/s/cm^2.

A power law function with an exponential
high-energy cutoff fits the spectrum equally well
with Epeak= 353 +/- 131 keV, alpha = -0.07 +/- 0.53.


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/"