[vsnet-grb-info 18381] GRB 160821A: Fermi-LAT detection of a bright burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19831
SUBJECT: GRB 160821A: Fermi-LAT detection of a bright burst
DATE:    16/08/21 21:40:46 GMT
FROM:    Julie McEnery at NASA/GSFC  <julie.e.mcenery at nasa.gov>

**J. McEnery, J. Racusin (NASA/GSFC) and Francesco Longo 
(INFN/Trieste) report on
behalf of the Fermi-LAT team:

At 20:36:44.33 on August 21, 2016, Fermi-LAT triggered
on high-energy emission from GRB 160821A, also detected by GBM (trigger 
493504474/
GRB160821857), and Swift-BAT (Siegel et al., GCN 19830).

The onboard location is

RA, Dec = 172.5, 43.0 (J2000)

with an error radius of 0.5 deg (90% containment, systematic error 
only).  This was 17 deg
from the LAT boresight at the time of the trigger.

Onboard LAT GRB detections are relatively rare, and imply that this GRB 
is exceptionally
bright at high energy gamma-rays. We strongly encourage follow-up 
observations.

The Fermi-LAT point of contact for this burst is Francesco Longo
(francesco.longo at trieste.infn.it <mailto:francesco.longo at 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.