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GCN Circular 28203

GRB 200803A: Fermi-LAT detection
2020-08-03T17:37:42Z (4 years ago)
Sara Cutini at INFN <>
S. Cutini (INFN Perugia), F. Longo (University & INFN Trieste), 
M. Axelsson (KTH & StockholmUniv.), M. Ohno (Hiroshima Univ. & Eotvos Univ.),  
F. Dirirsa (Univ. of Johannesburg), D.Kocesvki (NASA/MSFC), and N. Omodei (Stanford U.),
report on behalf of the Fermi-LAT team:

At 03:34:26.57 on August, 03, 2020 Fermi-LAT detected high-energy emission from GRB 200803A, 
which was also detected by Fermi-GBM (GCN 28196).

The best LAT on-ground location is found to be 

RA, Dec = 311.29, -63.08 (J2000)

with an error radius of 0.46 deg (90 % containment, statistical error only).

This was 39 deg from the LAT boresight at the time of the trigger, 
the Fermi-LAT entered  in the SAA at around 450 seconds after 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 0-450 s after the GBM trigger is 8.0e-6 +/- 2.3e-6 ph/cm2/s.
The estimated photon index above 100 MeV is -2.4+/-0.3.

The highest-energy photon is ~650 MeV  event which is observed ~200 seconds after the GBM trigger.

A Swift ToO has been approved for this burst.

The Fermi-LAT point of contact for this burst is Sara Cutini (

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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