{
  "bibcode": "2022GCN.31354....1U",
  "body": "A. Ursi, E. Menegoni (INAF/IAPS), F. Longo (Univ. Trieste and INFN\nTrieste), C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), P. Tempesta\n(TeleSpazio), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan,\nM. Cardillo, C. Casentini, Y. Evangelista, L. Foffano, G. Piano\n(INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, A. Di Piano,\nV. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi\n(INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois\n(INAF/OA-Cagliari), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), report\non behalf of the AGILE Team:\n\nThe AGILE satellite detected the long GRB 220101A at T0 = 2022-01-01\n05:11:22 (UTC), reported by Swift  BAT (GCN #31347, #31348), Swift XRT (GCN\n#31349), Swift UVOT (GCN #31351), and Fermi LAT (GCN #31350).\n\nThe burst is clearly visible in the AGILE scientific ratemeters of the\nSuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and\nAntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 80 s and\nit released a total number of 14577 counts in the SA detector (above a\nbackground rate of 100 Hz), 95830 counts in the MCAL detector (above a\nbackground rate of 1140 Hz), and 256390 counts in the AC detector (above a\nbackground rate of 3215 Hz). The AGILE ratemeters light curves can be found\nat http://www.agilescienceapp.it/notices/GRB220101A_AGILE_RM.png .\n\nThe event also triggered a partial high time resolution MCAL data\nacquisition, from T1 = 2022-01-01 05:11:21.50 +/- 0.01 s (UTC) to T2 =\n2022-01-01 05:11:55.74 +/- 0.01 s (UTC), and released 10934 counts in the\ndetector, above a background rate of 570 Hz. The time-integrated spectrum\nof the burst in this time interval can be fitted in the energy range\n0.4-100 MeV with a power-law with ph. ind. = -1.28 (-0.11/+0.11), resulting\nin a reduced chi-squared of 0.96 (84 d.o.f.) and a fluence of 7.8e-05\nergs/cm^2 (90% confidence level), in the same energy range.\n\nWe divided the data acquisition into four time intervals: interval a\n[T0-0.5 s, T0+10.0 s], interval b [T0+10.0 s, T0+17.0 s], interval c\n[T0+17.0 s, T0+24.0 s], and interval d [T0+24.0 s, T0+34.0 s]. The spectral\nanalysis in the energy range 0.4-100 MeV shows an evolution of the power\nlaw photon index in the first stages of the burst, passing from -0.98 to\n-1.70. Details are reported below:\n\n  | model | ph. ind.           | red chi^2 (dof) | fluence (erg/cm^2)\na | PL    | 0.98 (-0.29/+0.19) | 1.00 (75)       | (1.8+/-0.2)e-5\nb | PL    | 0.93 (-0.40/+0.22) | 0.98 (75)       | (8.3+/-0.8)e-6\nc | PL    | 1.31 (-0.22/+0.23) | 0.99 (75)       | (1.1+/-0.1)e-5\nd | PL    | 1.70 (-0.13/+0.29) | 1.05 (75)       | (2.6+/-0.3)e-5\n\nThe MCAL light curve can be found at:\nhttp://www.agilescienceapp.it/notices/GRB220101A_AGILE_MCAL.png .\n\nAdditional analysis of AGILE data is in progress. Automatic MCAL GRB alert\nNotices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html.",
  "circularId": 31354,
  "createdOn": 1641066800000,
  "email": "alessandro.ursi@gmail.com",
  "subject": "GRB 220101A: AGILE detection",
  "submitter": "Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>",
  "eventId": "GRB 220101A"
}