TITLE:   GCN CIRCULAR
NUMBER:  19802
SUBJECT: GRB 160816A: Fermi-LAT detection 
DATE:    16/08/16 23:15:28 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

J. L. Racusin (NASA/GSFC), F. Dirirsa (U. Johannesburg), F. Longo (University and INFN, Trieste), 
J. McEnery (NASA/GSFC), and G. Vianello (Stanford) report on behalf of the Fermi-LAT team:

At 17:30:58 on August 16, 2016 Fermi-LAT detected high-energy emission from GRB 160816A, which 
was also detected by Fermi-GBM (trigger 493061460 / 160816730). 

The best LAT on-ground location is found to be:
RA, Dec = 322.45, 37.16 (J2000)
with an error radius of 0.13 deg (90% containment, statistical error only). 

This was 35 deg from the LAT boresight at the time of the trigger and triggered an autonomous repoint 
of the spacecraft. 

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 9.5 GeV 
event which is observed ~1100 seconds after the GBM trigger.

A Swift ToO request has been approved for this burst.

The Fermi-LAT point of contact for this burst is Francesco Longo (francesco.longo@trieste.infn.it).

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.