GCN Circular 37341

S. Dalessi (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 14:55:06.83 UT on 28 August 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240828A (trigger 746549711/240828622).
which was also detected by AstroSat (S. Srijan et al. 2024, GCN 37328
Not found
 
 
), Fermi-LAT (R. Gupta et al. 2024, GCN 37331
Not found
 
 
), Swift-XRT (A.P. Beardmore et al. 2024, GCN 37337
Not found
 
 
), and KAIT (W. Zheng et al. 2024 37339)
The Fermi GBM on-ground location is consistent with the AstroSat, Fermi-LAT, Swift-XRT, and KAIT positions.

The angle from the Fermi LAT boresight is 97 degrees.

The GBM light curve multiple peaks with a duration (T90)
of about 41.2 s (50-300 keV). The time-averaged spectrum
from T0+0.002 to T0+44.225 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.96 +/- 0.01 and the cutoff energy,
parameterized as Epeak, is 850 +/- 30 keV.

The event fluence (10-1000 keV) in this time interval is
(8.05 +/- 0.07)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+38.8 s in the 10-1000 keV band is 18.6 +/- 0.4 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 820 +/- 30 keV, alpha = -0.96 +/- 0.01 and beta = -2.9 +/- 0.2.

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/"