[vsnet-grb-info 17883] GRB 160422A: Fermi-LAT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19329
SUBJECT: GRB 160422A: Fermi-LAT Detection
DATE:    16/04/22 19:26:41 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin at nasa.gov>

M. Yassine (LUPM, Montpellier), J. L. Racusin (NASA/GSFC), and N. Omodei (Stanford) report on 
behalf of the Fermi-LAT team:

Fermi LAT detected high-energy emission associated with GRB 160422A, which was also detected 
by Fermi GBM (trigger 483019143 / 160422499) at 11:59:00.81 on April 22, 2016.

The best LAT on-ground location is found to be:

RA, Dec (J2000) = 42.05, -57.9 

with an error radius of 0.07 deg (90% containment, statistical error only).

This was 80 deg from the LAT boresight at the time of the trigger, and triggered an autonomous 
repoint of the spacecraft.  The GRB became unocculted by the Earth and entered the LAT field 
of view at ~T0+400 seconds.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially correlated 
with the trigger with high significance.

The highest-energy photon is a 12 GeV event which is observed 770 seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is Manal Yassine (manal.yassine at lupm.in2p3.fr).

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.