GCN Circular 21827

E. Bissaldi (Politecnico & INFN Bari), D. Kocevski (NASA/GSFC),
G. Vianello (Stanford University), M. Arimoto (Waseda University)
and J. Racusin (NASA/GSFC) report on behalf of the Fermi-LAT team:


At 00:43:11.66 UT on September, 06, 2017 Fermi-LAT detected high-energy emission
from GRB 170906A, which was also detected by Fermi-GBM (trigger 526351393 / 170906030)
and Swift (Siegel et al., GCN #21821).

The best LAT on-ground location is found to be

RA, Dec = 203.94, -47.12 (J2000)

with an error radius of 0.10 deg (90 % containment, statistical error only).
This is consistent with the enhanced Swift-XRT position (Beardmore et al., GCN #21824).
This was 75 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 3.6 GeV event,
which is observed 200 seconds after the GBM trigger.

The Fermi-LAT point of contact for this burst is Judith Racusin (judith.racusin@nasa.gov).


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.