[vsnet-grb-info 13814] GRB 130828A: Fermi-LAT detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15128
SUBJECT: GRB 130828A: Fermi-LAT detection of a burst
DATE:    13/08/29 03:25:30 GMT
FROM:    Giacomo Vianello at SLAC  <giacomov at slac.stanford.edu>

G.Vianello (Stanford), E.Sonbas (NASA/GSFC/Adiyaman Univ.) report on
behalf of the Fermi-LAT team:

At 07:20:00.15 on 2013-08-28 Fermi LAT detected high energy emission
from GRB 130828A, which was also detected by Fermi-GBM (trigger
399367203).

The best LAT on-ground location is found to be RA, DEC 259.83, +28.00
(J2000) with an error radius of 0.3 deg (68% containment, statistical
error only), this was 40 deg from the LAT boresight at the time of the
trigger, and triggered an autonomous repoint of the spacecraft.

The data from the Fermi LAT show a significant increase (>> 5 sigma)
in the event rate within 2.3 degree of the best HITL GBM location
after the GBM trigger that is spatially and temporally correlated with
the GBM emission with high significance. More than 30 photons above
100 MeV and 2 photons above 1 GeV are observed within 1000 seconds.
The highest energy photon is a 1.5 GeV event which is observed 225
seconds after the GBM trigger.

The Fermi LAT point of contact for this burst is Eda Sonbas
(esonbas at slac.stanford.edu).

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.