[vsnet-grb-info 25983] GRB 200711A: Fermi-LAT marginal detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28083
SUBJECT: GRB 200711A: Fermi-LAT marginal detection
DATE:    20/07/12 18:47:27 GMT
FROM:    Milena Crnogorcevic at GSFC,UMD, Fermi  <milena.crnogorcevic at nasa.gov>

M. Crnogorcevic (Univ. of Maryland & NASA/GSFC), M. Kovacevic (INFN Perugia),
M. Ohno (Hiroshima Univ.), F. Longo (University & INFN Trieste),
report on behalf of the Fermi-LAT Collaboration:

On July, 11th, 2020, Fermi-LAT detected high-energy emission from GRB 200711A,
which was also detected by Fermi-GBM (trigger 616158277/200711461;
Poolakkil et al. GCN 28080) and Swift-BAT (Marshall et al. GCN 28078).

The best LAT on-ground location is found to be RA, Dec = 285.8, 0.2 (degrees, J2000) 
with an error radius of 0.4 deg (90% containment, statistical error only).
The 95% containment error is consistent with the Swift-XRT position 
(Osborne et al. GCN 28081).

This GRB was outside LAT FoV at the trigger time of the GBM and came
into the LAT FoV around 200 s after the trigger. The data from the 
Fermi-LAT in the time interval 200-600 s after the GBM trigger at the
Swift-XRT position show a marginal increase of the detection
significance of the high energy (GeV) photons for this burst.

The photon flux above 100 MeV in the time interval 200 - 600 s after
the GBM trigger is 3.3e-6 +/- 1.9e-6 ph/cm2/s.

The highest-energy photon is a 5.7 GeV event which is observed 542 seconds
after the GBM trigger.

The Fermi-LAT point of contact for this burst is
Milena Crnogorcevic (mcrnogor at astro.umd.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.