[vsnet-grb-info 22580] GRB 190530A: Fermi-LAT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24679
SUBJECT: GRB 190530A: Fermi-LAT detection  
DATE:    19/05/30 18:20:18 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin at nasa.gov>

F. Longo (University and INFN, Trieste), J. L. Racusin (NASA/GSFC), N. Omodei (Stanford), and 
E.Bissaldi (Politecnico & INFN Bari) report on behalf of the Fermi-LAT Collaboration:

At 10:19:08 UT on 2019-05-30, Fermi-LAT triggered on high-energy emission from long GRB 190530A, 
which was also detected by Fermi-GBM (GCN 24676) and AGILE-MCAL (GCN 24678).

The best LAT on-ground location is found to be:
RA, Dec = 120.76, 35.5 (J2000) 
with an error radius of 0.12 deg (90% containment, statistical error only).

This was 63 deg from the LAT boresight at the time of the trigger and 3.5 deg from the center of the GBM 
localization (GCN 24676).

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

The highest-energy photon is a 8.7 GeV event which is observed 96 seconds after the GBM trigger.
The photon flux above 100 MeV in the time interval 0-200s after the GBM trigger is 2.9 e-04 ph/cm2/s 
+/- 2.9 e-05.

The estimated photon index above 100 MeV is -2.7 +/- 0.1.

The Fermi-LAT point of contact for this burst is Francesco Longo (francesco.longo at ts.infn.it).

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.