GRB 221027A: AGILE detection
Abstract
The AGILE satellite detected the GRB 221027A at T0 = 2022-10-27 04:09:34 s (UTC), reported by Fermi GBM (GCNs #32861, #32866) and Fermi LAT (GCN #32862). The burst is 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 10 s and it released a total number of 11040 counts in the MCAL detector (above a background rate of 1180 Hz), and 30890 counts in the AC detector (above a background rate of 3250 Hz). The AGILE ratemeters light curves can be found at http://www.agilescienceapp.it/notices/GRB221027A_AGILE_RM.png . The event also triggered a high time resolution MCAL data acquisition, from T0-22.42 s to T0+7.94 s (UTC), and released 5086 counts in the detector, above a background rate of 472 Hz. The MCAL light curve can be found at http://www.agilescienceapp.it/notices/GRB221027A_080667_593928574.000000.png . The time-integrated spectrum of the burst between T0 and T0+3s be fitted in the energy range 0.4-10 MeV with a power-law with ph. ind. = -2.31 (-0.69/+1.26), resulting in a reduced chi-squared of 1.44 (48 d.o.f.) and a fluence of 1.8e-06 ergs/cm^2 (90% confidence level), in the same energy range. At the T0, the event was 67 deg off-axis. 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.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- October 2022
- Bibcode:
- 2022GCN.32884....1U