[vsnet-grb-info 6642] GRB 080916C: Fermi LAT observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8246
SUBJECT: GRB 080916C: Fermi LAT observation
DATE:    08/09/16 18:25:23 GMT
FROM:    Nicola Omodei at INFN(Pisa)/GLAST  <nicola.omodei at pi.infn.it>

H. Tajima (SLAC), J. Bregeon (INFN Pisa), J. Chiang (SLAC), G. Thayer (SLAC)
on behalf of the Fermi LAT team:

We report a detection by the Fermi Large Area Telescope (LAT) of 
emission from the long GRB 080916C, which was triggered by the Fermi 
Gamma-ray Burst Monitor (GBM) at 00:12:45 UT on September 16th 2008 (GCN 
8245). The angle of the GBM best position (RA, Dec=121.8,-61.3) with 
respect to the LAT boresight was 52 degrees at the time of the trigger, 
which is close the edge of our field of view.

The data from the Fermi LAT shows a significant increase in the event 
rate within 10 degrees of the GBM location after the GBM trigger that is 
spatially and temporally correlated with the GBM emission with high 
significance. More than 10 photons are observed above 1 GeV during this 
time.

The best LAT on-ground localization is found to be (RA,Dec=119.88, 
-56.59) with a 90% containment radius of 0.13 deg (statistical; 68% 
containment radius: 0.09 deg, preliminary systematic error is less than 
0.1 deg) which is consistent with the GBM localization.

This circular is an official product of the Fermi LAT team.