[vsnet-grb-info 21287] GRB 181028A: Fermi-LAT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23386
SUBJECT: GRB 181028A: Fermi-LAT detection
DATE:    18/10/29 00:05:28 GMT
FROM:    Magnus Axelsson at Stockholm U.  <magaxe at kth.se>

M. Axelsson (KTH and Stockholm Univ.), D. Kocevski (NASA/MSFC), E. Bissaldi (Politecnico & INFN Bari) and M. Yassine (Univ. & INFN Trieste) report on behalf of the Fermi-LAT team:

On October 28, 2018, Fermi-LAT detected high-energy emission from GRB 181028A, which was also detected by Fermi-GBM (trigger 562428587).

The best LAT on-ground location is found to be

RA, Dec = 88.9, -22.0 (J2000)

with an error radius of 0.4 deg (90 % containment, statistical error only). This is 4.9 deg from the GBM location.

This was 60 deg from the LAT boresight at the time of the GBM trigger: 14:09:42.53 UT.

The data from the Fermi-LAT in the time interval 0-300s after the GBM trigger show a significant increase in the event rate that is spatially correlated with the trigger with very high significance. The highest-energy photon is a 1.7 GeV event which is observed 295 seconds after the GBM trigger.


The Fermi-LAT point of contact for this burst is Manal Yassine (mychbib at gmail.com<mailto:mychbib at gmail.com>).

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