[vsnet-grb-info 16708] GRB 150702A: Fermi-LAT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17989
SUBJECT: GRB 150702A: Fermi-LAT detection
DATE:    15/07/04 22:56:29 GMT
FROM:    Giacomo Vianello at SLAC  <giacomov at slac.stanford.edu>

G.Vianello (Stanford University),  M.E. Monzani (SLAC), M. Axelsson
(Stockholm University)

report on behalf of the Fermi-LAT team:

On July, 02, 2015 Fermi-LAT detected high-energy emission from GRB
150702A, which triggered Fermi-GBM at 23:56:38.55 UT (trigger
457574201 / 150702998).

The LAT data from this burst were made available to the Fermi
collaboration and to the public with an unusually long delay, due to
an issue with ground software which affected the event reconstruction
pipeline. This issue has now been solved.

The best LAT on-ground location is found to be

RA, Dec = 52.78, -57.00 (J2000)

with an error radius of 0.36 deg (90 % containment, statistical error only).

The GRB was outside the field of view of the LAT at the trigger time,
but entered the FOV ~500 s after the trigger and exited again ~3000 s
after the trigger.

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

The highest-energy photon is a 800 MeV event which is observed ~1200
seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is Magnus Axelsson
(magnusa at astro.su.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.