GCN Circular 35227
Subject
GRB 231129C: Fermi GBM Observation of a very bright GRB
Date
2023-11-30T04:57:42Z (a year ago)
From
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov>
Via
Web form
V. Sharma (NASA-GSFC/UMBC), C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 19:10:18.11 UT on 29 November 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231129C (trigger 722977823/231129799), which was also detected by MAXI/GSC (Y. Kawakubo et al. 2023, GCN 35223). The Fermi GBM Final Real-time Localization is reported (GCN 35221, GCN 35217).
The angle from the Fermi LAT boresight at the GBM trigger time is 50 degrees.
The GBM light curve shows a very bright, single pulse starting from about T0+0 s to T0+15 s. The calculated duration (T90) is about 6 s (50-300 keV). The time-averaged spectrum from T0+0 s to T0+7 s can be fit by a Band function with Epeak = 215 +/- 2 keV, alpha = -0.11 +/- 0.01, and beta = -2.79 +/- 0.03.
The event fluence (10-1000 keV) in this time interval is (8.41 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.8 s in the 10-1000 keV band is 102 +/- 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/"