[vsnet-grb-info 26030] GRB 200716C: Fermi-LAT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28130
SUBJECT: GRB 200716C: Fermi-LAT detection 
DATE:    20/07/17 06:53:04 GMT
FROM:    Nicola Omodei at Stanford U.  <nicola.omodei at slac.stanford.edu>

M. Ohno (Hiroshima Univ/Eotvos Univ.), M. Arimoto (Kanazawa Univ.), N. Di Lalla, N. Omodei (Stanford University), F. Longo (University and INFN, Trieste),  
report on behalf of the Fermi-LAT Collaboration:

On July, 16th, 2020, Fermi-LAT detected high-energy emission from GRB 200716C, which was also detected by Fermi-GBM (trigger 616633066.180458/200716957; Fermi GBM Team GCN 28123) and Swift (Ukwatta et al. GCN 28124).

The best LAT on-ground location is found to be RA, Dec = 195.7, 29.9 (degrees, J2000) with an error radius of 0.3 deg (90% containment, statistical error only).
The best LAT position is consistent with the Swift position. This was 6 deg from the LAT boresight at the time of the GBM trigger: T0 =  22:57:41 UT.

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

The photon flux above 100 MeV in the time interval 0-1000 s after the GBM trigger is 5.3e-6 +/- 2.0e-6 ph/cm2/s.
The estimated photon index above 100 MeV is -1.9+/-0.2.

The highest-energy photon is a 8.2 GeV event which is observed 152 seconds after the GBM trigger.

The Fermi-LAT point of contact for this burst is
Nicola Omodei (nicola.omodei at 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.