GCN Circular 37042
Subject
GRB 240805A: Fermi-LAT detection
Date
2024-08-05T14:41:11Z (2 months ago)
Edited On
2024-08-05T21:22:38Z (2 months ago)
From
Rahul Gupta at NASA GSFC <rahul.gupta@nasa.gov>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Lorenzo Scotton at UAH <lscottongcn@outlook.com>
Via
email
R. Gupta (NASA GSFC), A. Holzmann (DF, University of Buenos Aires, Argentina), and F. Longo (University and INFN, Trieste) report on behalf of the Fermi-LAT Collaboration:
At 02:02:20.31 UT on August 05, 2024, Fermi-LAT detected high-energy emission from GRB 240805A which was also detected by Fermi-GBM (trigger 744516145 / 240805085, GCN 37031), Swift/BAT (GCN 37032), and INTEGRAL (GCN 37037).
The best LAT on-ground location is found to be
RA, Dec = 190.45, -54.02 (J2000)
with an error radius of 0.45 deg (90% containment, statistical error only).
This was 59 deg from the LAT boresight at the time of the trigger.
The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance. The photon flux above 100 MeV in the time interval 0-100 s after the GBM trigger is (3.6 +/- 1.3) E-5 ph/cm2/s. The estimated photon index above 100 MeV is -2.0 +/- 0.3.
The highest-energy photon is a 1.6 GeV event which is observed about 17 seconds after the GBM trigger.
The Fermi-LAT point of contact for this burst is Lorenzo Scotton (lorenzo.scotton AT uah.edu)
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.