TITLE:   GCN CIRCULAR
NUMBER:  31784
SUBJECT: GRB 220323A: AGILE/MCAL detection
DATE:    22/03/23 15:14:50 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

A. Ursi (INAF/IAPS), M. Romani (INAF/OA-Brera), C. Pittori, F. Verrecchia
(SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A.
Argan, M. Cardillo, C. Casentini, Y. Evangelista, L. Foffano, E. Menegoni,
G. Piano (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, A.
Di Piano, V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M.
Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), F.
Longo (Univ. Trieste and INFN Trieste), and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:

The AGILE MiniCALorimeter (MCAL; 0.4-100 MeV) detected the short GRB
220323A at T0 = 2022-03-23 12:10:11 (UTC), reported by Fermi GBM (GCN
#31782).

The event lasted 0.35 s and released 295 counts in the detector, above a
background rate of 630 Hz. The time-integrated spectrum of the burst can be
fitted in the energy range 0.4-2 MeV with a power-law with ph.ind = 2.44
(-0.70/+1.13), resulting in a reduced chi-squared of 1.06 (21 d.o.f.) and a
fluence of 5.6e-07 erg/cm^2 (90% confidence level), in the same energy
range. The MCAL light curve can be found at
http://www.agilescienceapp.it/notices/077531_GRB_575122215.552228.png . At
the T0, the event was 134 deg off-axis.

The burst is also clearly visible in the AGILE scientific ratemeters of the
MCAL detector, where it released a total number of 1550 counts (above a
background rate of 1230 Hz). The AGILE MCAL ratemeters light curve can be
found at http://www.agilescienceapp.it/notices/GRB220323A_AGILE_RM.png .

Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html. Please
note that in the MCAL notice #575122215 the T0 was affected by a temporal
shift of about +4.0 sec due to episodic automated ground software problems
which are then corrected offline.