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GCN Circular 36910

Subject
GRB 240720A: Fermi GBM observation
Date
2024-07-20T16:27:50Z (4 months ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
Via
Web form
C. Fletcher (USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 00:24:51.22 UT on 20 July 2024, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 240720A (trigger 743127896 / 240720017),
which was also detected by the Swift/BAT (Gupta et al. 2024, GCN 36909) and INTEGRAL SPI/ACS (trigger 10797).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 47 degrees.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 1.8 s (50-300 keV).
The time-averaged spectrum from T0+0.002 s to T0+2.176 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.66 +/- 0.07 and
the cutoff energy, parameterized as Epeak, is 1069 +/- 172 keV.

The event fluence (10-1000 keV) in this time interval is
(3.9 +/- 0.1)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.896 s in the 10-1000 keV band
is 9.1 +/- 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/"
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