GCN Circular 31186
Subject
GRB 211204C: Fermi GBM detection
Event
Date
2021-12-08T13:29:44Z (4 years ago)
From
Boyan A. Hristov at UAH <bah0046@uah.edu>
Boyan A. Hristov (UAH) reports on behalf of the Fermi GBM Team:
At 21:37:00.55 UT on 04 December 2021, the Fermi Gamma-Ray Burst
Monitor (GBM) triggered and located GRB 211204C (trigger 660346625
/ 211204901), which was also detected by GECAM-B (Zhang et al. 2021,
GCN 31173), INTEGRAL SPI_ACS (trigger num. 9552), Swift/BAT-GUANO
(Tohuvavohu et al., GCN 31174), AstroSat CZTI detection (Waratkar et
al., GCN 31178) and was triangulated by IPN (Ridnaia et al., GCN
31177).
The GECAM localization and the IPN triangulation are consistent with
the GBM localization (GCN 31171).
The GBM light curve consists of a single spike with a duration (T90)
of about 17.41 s +/- 2.00 s (50-300 keV). The time-averaged spectrum
from T0+0.003 s to T0+19.456 s is adequately fit by a Band function
with Epeak = 287.90 +/- 34.30 keV, alpha = -0.71 +/- 0.09, and beta =
-2.37 +/- 0.19.
The event fluence (10-1000 keV) in this time interval is (2.827 +/-
0.105)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting
from T0+7.040 s in the 10-1000 keV band is 19.9063 +/- 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/