GCN Circular 38436

E. Bissaldi (Politecnico and INFN Bari), A. Holzmann Airasca (UniTrento and INFN Bari)
and T. Khalil (Johannesburg Univ) report on behalf of the Fermi-LAT Collaboration:



On Dec 4, 2024, Fermi-LAT detected high-energy emission from GRB 241204A,
which was also detected by Fermi-GBM (trigger 754976367 / 241204.152).

The best LAT on-ground location is found to be:

RA, Dec =  316.50, 6.55 (J2000),

with an error radius of 0.5 deg (90 % containment, statistical error only).
This was 26 deg from the LAT boresight at the time of the GBM trigger (T0 = 03:39:22.51 UT).

The data from the Fermi-LAT show a significant increase in the event rate
that is spatially and temporally correlated with the GBM emission
with high significance.
The photon flux above 100 MeV in the time interval 0 - 350 s after the GBM trigger
is (1.7 +/- 0.4) E-5 ph/cm2/s.
The estimated photon index above 100 MeV is 2.8 +/- 0.4.
The highest-energy photon is a 260 MeV event which is observed ~16 seconds after the GBM trigger.

The Fermi-LAT point of contact for this burst is Tamador Khalil (tamtam2030@gmail.com).



The Fermi-LAT is a pair conversion telescope designed to cover
the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between
NASA and DOE in the U.S. and many scientific institutions
across France, Italy, Japan and Sweden.