GCN Circular 35578

R. Hamburg (CNRS/IN2P3) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 11:03:14.11 UT on 15 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240115A (trigger 727009399/240115461),
which was also detected by Swift/BAT-GUANO (DeLaunay et al. 2024, GCN 35557
Not found
 
 
).
The Fermi Final Real-time Localization is reported in GCN 35537
Not found
 
 
.

The angle from the Fermi LAT boresight is 37 degrees.

The GBM light curve consists of one main pulse with a duration (T90)
of about 1.79 s (50-300 keV). The time-averaged spectrum
from T0-0.26 to T0+0.77 s is best fit by a power law function 
with an exponential high-energy cutoff.
The power law index is -0.7 +/- 0.2 and the cutoff energy,
parameterized as Epeak, is 450 +/- 137 keV.

The event fluence (10-1000 keV) in this time interval is
(4.8 +/- 0.6)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.64 s in the 10-1000 keV band is 3.4 +/- 1.0 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/"