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GCN Circular 32856

GRB 221023A: AGILE/GRID analysis
2022-10-26T15:16:15Z (a year ago)
Francesco Verrecchia at SSDC,INAF-OAR <>
F. Verrecchia (SSDC, and INAF/OAR), C. Pittori (SSDC, and INAF/OAR)
A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata),
C. Casentini (INAF/IAPS), A. Giuliani (INAF/IASF-Mi), F. Longo (Univ.
Trieste and INFN Trieste), L. Foffano (INAF/IAPS), F. Lucarelli (SSDC,
and INAF/OAR), M. Romani(INAF/OA-Brera), G. Piano, A. Argan, M. Cardillo,
Y. Evangelista, E. Menegoni (INAF/IAPS), A. Bulgarelli, A. Di Piano,
V. Fioretti, G. Panebianco, N. Parmiggiani (INAF/OAS), M. Marisaldi
(INAF/OAS, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari),
I. Donnarumma (ASI), and P. Tempesta (TeleSpazio), report on
behalf of the AGILE Team:

The Gamma-Ray Imaging Detector (GRID) of AGILE detected gamma-ray
transient emission consistent with the long GRB 221023A reported
by AGILE/MCAL (GCN #32825) at T0 = 2022-10-23 20:41:34 s (UTC), also
detected by Fermi/GBM (GCN #32826, #32845), Fermi/LAT (GCN #82831)
and Konus-Wind (GCN #32849).
A refined AGILE/GRID data analysis in the energy range 30 MeV - 10 GeV
shows a detection with a statistical significance of about 4.3 sigma
overa time integration of 50 s starting at the T0 of GRB 221023A,
at a sky position with Galactic coordinates l=28 deg, b=53 deg, with
and an error radius of 4 deg (90% statistical + systematic error;
R.A.= 232 deg, Decl.= 19 deg (J2000)).
The GRID error circle includes the LAT position.
During the 120s integration, we detected a total of 22 events (11
background events estimated through a Li&Ma analysis), 16 events at
energies above 100 MeV, and 2 events above 1 GeV.

These measurements were obtained with AGILE observing a large portion
of the sky in spinning mode. Additional analysis of AGILE data is in
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