[vsnet-grb-info 26648] GRB 201021C: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28748
SUBJECT: GRB 201021C: Fermi GBM detection
DATE:    20/10/22 15:41:24 GMT
FROM:    Stephen Lesage at Fermi-GBM Team  <sjl0014 at uah.edu>

S. Lesage (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 20:27:21.92 UT on 21 October 2020, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 201021C (trigger 625004846 / 201021852)
which was also detected by the Swift/BAT (A. Y. Lien et al. 2020, GCN
28730).
The Fermi GBM on-ground localization is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is ~59
degrees.

The GBM light curve shows a single bright peak
with a duration (T90) of about 35.3 s (50-300 keV).
The time-averaged spectrum from T0-5.9 s to T0+29.4 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.1 +/- 0.2 and
the cutoff energy, parameterized as Epeak, is 131.1 +/- 28.2 keV.

The event fluence (10-1000 keV) in this time interval is
(1.7 +/- 0.2)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0-1.9 s in the 10-1000 keV band
is 1.82 +/- 0.2 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/"