[vsnet-grb-info 14284] GRB 131216A: Fermi-LAT detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15598
SUBJECT: GRB 131216A: Fermi-LAT detection of a burst
DATE:    13/12/16 14:51:54 GMT
FROM:    Peter Veres at ELTE,Budapest  <veresp at gmail.com>

P. Veres (Penn State), D. Kocevski (NASA/Goddard), E. Bissaldi
(University & INFN Trieste), R. Desiante (University of Udine and INFN
Trieste), J. Racusin (NASA/Goddard), report on behalf of the Fermi-LAT
team:

The Fermi Large Area Telescope (LAT) detected emission from GRB
131216A, also detected by GBM (trigger 408851795/131216081) at T0 =
01:56:32.06 UT on December 16, 2013.

The GBM location was initially inside the LAT field of view at an
angle of 44 degrees to the LAT boresight and triggered an autonomous
repoint of the spacecraft. However, LAT did not collect data while in
the South Atlantic Anomaly (SAA) from T0+200 to T0+800 s. No
significant excess is seen using standard analysis procedures.

Using the LAT Low Energy (LLE) event selection, over 120 counts above
background were detected within a 0.3 s interval coinciding with the
time of the GBM emission. This data selection has insufficient spatial
resolution to provide a reliable LAT localization. Since an excess of
events were not seen using the standard analysis selection, this
detection is likely due to low energy gamma-rays (below 100 MeV).

The Fermi LAT point of contact for this burst is Peter Veres  (puv2 at psu.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.