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GCN Circular 31611

Subject
GRB 220219A: AGILE/MCAL detection
Date
2022-02-19T14:20:46Z (3 years ago)
From
Alessandro Ursi at INAF/IAPS <alessandro.ursi@gmail.com>
A. Ursi (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), 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,
C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti,
F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi
(INAF/OAS-Bologna, and Bergen University), A. Trois (INAF/OA-Cagliari), I.
Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani
(INAF/IASF-Mi), report on behalf of the AGILE Team:

The AGILE Mini-CALorimeter (MCAL) detected the GRB 220219A T0 = 2022-02-19
11:21:35.02 +/- 0.01 s (UTC), reported by Fermi GBM (GCN #31609Loading...
 
 ).

The event lasted about 9.5 s and released a total number of 7450 counts in
the MCAL detector (in the 0.4-100 MeV energy range), above an average
background rate of 597 Hz. The MCAL light curve can be found at
http://www.agilescienceapp.it/notices/077070_GRB_MCAL_572354495.021853.png
. The time-integrated spectrum of the burst, from T0-3.0 s to T0+6.5 s, can
be fitted in the energy range 0.4-10 MeV with a power-law with ph.ind. =
-2.83 (-0.24,+0.28), resulting in a reduced chi-squared of 0.78 (48 d.o.f.)
and a fluence of 1.26e-05 erg/cm^2 (90% confidence level), in the same
energy range.

The burst is also clearly visible in the AGILE scientific ratemeters of the
MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV)
detectors. The event lasted about 9 s and it released a total number of
13810 counts in the MCAL detector (above a background rate of 1210 Hz), and
33110 counts in the AC detector (above a background rate of 3370 Hz). The
AGILE ratemeter light curves can be found at
http://www.agilescienceapp.it/notices/GRB220219A_AGILE_RM.png . At the T0,
the event was 140 deg off-axis.

The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the
energy range 0.4-100 MeV. 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.