[vsnet-grb-info 11713] GRB 120323A: Fermi LAT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13104
SUBJECT: GRB 120323A: Fermi LAT observations
DATE:    12/03/25 17:28:31 GMT
FROM:    Thomas P.H. Tam at Nat.Tsing Hua U.  <grbtom at gmail.com>

P.H.T. Tam and A.K.H. Kong (NTHU) report:

We report on the Fermi/LAT observations of the short (~0.5s) and very
bright GRB 120323A
that triggered Fermi/GBM (Gruber & Connaughton, GCN 13099), Konus-Wind and
a few other detectors (Golenetskii at al., GCN 13102). Using the 10-degree
radius data centered on the IPN Triangulation position (GCN 13102), we did
not find any significant emission above 60 MeV from this circular region
during the prompt emission nor between 0.5 and 100 seconds after the
Konus-Wind
trigger time (T0).

Extrapolating the high-energy photon index, beta, which is 2.9, in the
best-fit
Band function (GCN 13103) to the LAT energy range, we derived 90% C.L.
upper
limits (0.1-10 GeV) for the following periods as tabulated below
(calculated
using Feldman & Cousins, 1998 formulation):

Epoch U.L. (ph/cm2-s)
T0 to T0+0.5s 3.5e-3
T0+0.5s to T0+1.0s 3.5e-3
T0+1.0s to T0+3.0s 8.7e-4
T0+3.0s to T0+10s 2.5e-5
T0+10s to T0+100s 1.3e-5