GCN Circular 21080

E. Bissaldi (Politecnico & INFN Bari), M. Axelsson (Stockholm Univ. & KTH),
and F. Longo (University & INFN, Trieste) report on behalf of the Fermi-LAT team:


At 05:12:25.73 UT on May 10, 2017 Fermi-LAT detected high-energy emission
from GRB 170510A, which was also detected by Fermi-GBM (trigger 516085950/170510217).
The best LAT on-ground location is found to be

RA, Dec = 159.91, -39.32 (J2000)

with an error radius of 0.34 deg (90 % containment, statistical error only).
This was ~67 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 1.8 GeV event which is observed 410 seconds
after the GBM trigger.
A total of 15 photons were detected in the first 500 seconds after the trigger,
after which time the spacecraft entered the SAA.

A Swift ToO has been approved for this burst.

The Fermi-LAT point of contact for this burst is
Elisabetta Bissaldi (elisabetta.bissaldi@ba.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.