GCN Circular 28714

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, 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 GRB 201020B at T0 = 2020-10-20
17:34:03.78 +/- 0.01 s (UTC), reported by Fermi/GBM (GCNs #28702 and
#28710).

The event lasted about 5 s and released a total number of 3250 counts in
the detector (in the 0.4-100 MeV energy range), above an average background
rate of 550 Hz. The MCAL light curve can be found at
http://www.agilescienceapp.it/notices/GRB_069336_525794310.907011.png .

The time-integrated spectrum of the burst can be fitted in the energy range
0.4-20 MeV with a single power-law with ph.ind. = -2.78 -0.03/+0.04,
resulting in a reduced chi-squared of 1.05 (89 d.o.f.) and a fluence of
4.56e-06 ergs/cm^2 (90% confidence level), in the same energy range.

The burst is clearly visible in the AGILE scientific ratemeters of the
SuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and
AntiCoincidence (AC; 50-200 keV) detectors. The event lasted ~27 s and
released a total number of 5856 counts in the SA detector (above a
background rate of 80 Hz); it lasted ~17.5 s and released a total number of
66750 counts in the AC detector (above a background rate of 3670 Hz); it
lasted ~5 s and released a total number of 7506 counts in the MCAL detector
(above a background rate of 1260 Hz). The AGILE ratemeter light curves can
be found at http://www.agilescienceapp.it/notices/GRB_201020B_AGILE_RM.png .

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.