TITLE:   GCN CIRCULAR
NUMBER:  29017
SUBJECT: GRB 201208A: Fermi GBM observation
DATE:    20/12/09 18:43:38 GMT
FROM:    Rachel Dunwoody at UCD  <rachel.dunwoody@ucdconnect.ie>

R,Dunwoody (UCD), J.Mangan (UCD) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

At 06:03:23.25 UT on 08 December 2020, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 201208A (trigger 629100208 / 201208252)
which was also detected by the Fermi/LAT (F. Dirirsa et al. 2020, GCN 29003)
The Fermi GBM Final Real-time Localization (GCN 28998) is consistent with
the Fermi/LAT position.
This source was also detected by AstroSat (D. Nadella et al. 2020,
GCN29001).

The angle from the Fermi LAT boresight at the GBM trigger time is 11
degrees.

The GBM light curve consists of one main pulse
with a duration (T90) of about 45 s (50-300 keV).
The time-averaged spectrum from T0-14 s to T0+34 s is
best fit by a power law with an exponential high-energy cutoff.
The power law index is -0.87 +/- 0.07 and the cutoff energy,
parameterized as Epeak, is 254 +/- 24.

The event fluence (10-1000 keV) in this time interval is
 (1.07 +/- 0.22)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+12 s in the 10-1000 keV band
is 5.1 +/- 0.3 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/"