TITLE:   GCN CIRCULAR
NUMBER:  37747
SUBJECT: GRB 241008A: Fermi-LAT detection
DATE:    24/10/09 14:41:47 GMT
FROM:    Rahul Gupta at NASA GSFC <rahul.gupta@nasa.gov>

R. Gupta (NASA GSFC), C. Bartolini (UniTrento e INFN Bari), and J. Racusin (NASA GSFC) report on behalf of the Fermi-LAT Collaboration:

On Oct 08, 2024, Fermi-LAT detected high-energy emission from GRB 241008A, which was also detected by Fermi-GBM (trigger 750117609/ 241008917, GCN 37740).

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

RA, Dec = 112.84, -9.40 (J2000)

with an error radius of 0.23 deg (90 % containment, statistical error only).

This was 82 deg from the LAT boresight at the time of the GBM trigger: T0 = 22:00:04 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 0-2050 s after the GBM trigger is (2.1 +/- 0.7) E-6 ph/cm2/s. The estimated photon index above 100 MeV is -2.0 +/- 0.3.

The highest-energy photon is a 1.8 GeV event which is observed ~1667 seconds after the GBM trigger.

The Fermi-LAT point of contact for this burst is Rahul Gupta (rahul.gupta@nasa.gov).

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.