GCN Circular 38524
Subject
GRB 241209C: Fermi GBM Observation
Date
2024-12-10T14:15:29Z (25 days ago)
From
Christian Malacaria at INAF-OAR <cmalacaria.astro@gmail.com>
Via
Web form
C. Malacaria (INAF-OAR) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 07:22:54.60 UT on 09 December 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 241209C (trigger 755421779/241209308),
which was also detected by AstroSat (J. Joshi et al. 2024, GCN 38490)
and Swift/BAT-GUANO (J. DeLaunay et al. 2024, GCN 38501).
The GBM Final Real-time Localization is reported in GCN 38482.
The angle from the Fermi LAT boresight is 36 degrees.
The GBM light curve consists of a single emission episode with a duration (T90)
of about 11 s (50-300 keV). The time-averaged spectrum
from T0-4.1 to T0+9.2 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.4 +/- 0.1 and the cutoff energy,
parameterized as Epeak, is 270 +/- 20 keV.
The event fluence (10-1000 keV) in this time interval is
(4 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.8 s in the 10-1000 keV band is 3.3 +/- 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/"