[vsnet-grb-info 19898] GRB 171010A: Fermi-LAT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21985
SUBJECT: GRB 171010A: Fermi-LAT detection
DATE:    17/10/11 00:42:09 GMT
FROM:    Nicola Omodei at Stanford U.  <nicola.omodei at slac.stanford.edu>

N. Omodei (Stanford U.), G. Vianello (Stanford U.), B. Ahlgren (KTH)

report on behalf of the Fermi-LAT team:

At 19:00:50.58 on October, 10, 2017 Fermi-LAT detected high-energy emission from GRB 171010A, which was also detected by Fermi-GBM (trigger 529354855 / 171010792). 

The best LAT on-ground location is found to be:
 RA, Dec = 66.74, -10.53 (J2000) 
 with an error radius of 0.20 deg (90 % containment, statistical error only). 

The GRB was outside the LAT field of view at the time of the GBM 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 correlated with the trigger with high significance. 

The highest-energy photon is a 7 GeV event which is observed 768 seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is  B. Ahlgren (bjornah at kth.se).

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.