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GCN Circular 23350

GRB 181020A: Fermi-LAT detection
2018-10-21T01:47:35Z (6 years ago)
Magnus Axelsson at Stockholm U. <>
M. Axelsson (KTH and Stockholm University) reports on behalf of the Fermi-LAT team:

On October 20, 2018, Fermi-LAT detected high-energy emission from GRB 181020A, which was also detected by Swift (Moss et al. 2018, GCN 23349) and by Fermi-GBM (trigger 561754838).

The best LAT on-ground location is found to be

RA, Dec = 14.1, -47.3 (J2000)

with an error radius of 1.1 deg (90 % containment, statistical error only). This is 0.19 deg from the Swift location.

This was 50 deg from the LAT boresight at the time of the GBM trigger: 19:00:33.30 UT.

The data from the Fermi-LAT in the time interval 0-50s after the GBM trigger show a significant increase in the event rate that is spatially and temporally correlated with the trigger with very high significance. The highest-energy photon is a 930 MeV event which is observed 18 seconds after the GBM trigger.

The Fermi-LAT point of contact for this burst is Masanori Ohno (<>).

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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