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GCN Circular 22883

GRB 180703A: Fermi-LAT detection
2018-07-04T01:57:55Z (6 years ago)
Judith Racusin at GSFC <>
J. L. Racusin (NASA/GSFC), M. Crnogor��evi�� (UMD), M. Axelsson (KTH and Stockholm Univ.), 
A. Barker (George Washington), G. Vianello (Stanford), and M. Arimoto (Kanazawa University), 
report on behalf of the Fermi-LAT team:

At 21:01:40.50 on July, 03, 2018 Fermi-LAT detected high-energy emission from GRB 180703A, 
which was also detected by Fermi-GBM (trigger 552344505 / 180703876).

The best LAT on-ground location is found to be
RA, Dec = 6.54, -67.1 (J2000)
with an error radius of 0.3 deg (90% containment, statistical error only).

This was 48 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 highest-energy photon is a ~930 MeV event which is observed at 40 seconds after the GBM trigger.

A Swift ToO has been approved for this burst.

The Fermi-LAT point of contact for this burst is Judith Racusin (

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.
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