[vsnet-grb-info 23475] GRB 190829A: Fermi-LAT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25574
SUBJECT: GRB 190829A: Fermi-LAT Upper Limits
DATE:    19/08/30 12:37:54 GMT
FROM:    Frederic Piron at CNRS/IN2P3/LUPM  <piron at in2p3.fr>

F. Piron (CNRS/IN2P3/LUPM), F. Longo (Univ. and INFN Trieste), M. 
Axelsson (KTH and Stockholm Univ.), M. Arimoto (Kanazawa Univ.), J. L. 
Racusin (NASA/GSFC) and E. Bissaldi (Politecnico and INFN Bari) report 
on behalf of the Fermi-LAT Collaboration:

Fermi-LAT observed the position of GRB 190829A, which was detected by 
Fermi-GBM (GCN Circ. 25551), Swift (GCN Circ. 25552), and H.E.S.S. (GCN 
Circ. 25566). The GRB position was in the LAT field of view at the time 
of the GBM trigger (T0= 2019-08-29 19:55:53 UTC), and remained visible 
until ~T0+1100 s. No high-energy gamma-ray emission was detected by the 
LAT in the initial interval or any subsequent intervals, including 
during the H.E.S.S. observations.

LAT upper limits (95% confidence level, 100 MeV - 1 GeV), assuming a 
photon index of -2.0, cover the following intervals:

Time Interval                                 Energy Flux (erg/cm2/s)    
     Photon Flux (ph/cm2/s)

0-1.1 ks                         5.3e-10                              1.3e-6
0-10 ks                        3.2e-10                              7.9e-7
10-30 ks                      1.4e-10     3.5e-7
15-30 ks (H.E.S.S. interval)            1.8e-10                      4.3e-7


The Fermi-LAT point of contact for this burst is Frederic Piron 
(piron at in2p3.fr).

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.