TITLE: GCN CIRCULAR NUMBER: 31780 SUBJECT: GRB 220316A: AstroSat CZTI detection DATE: 22/03/22 13:32:56 GMT FROM: Gaurav Waratkar at IIT,Bombay R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed detection of a long GRB 220316A which was also detected by Fermi - GBM (TrigNum - 669122742), and Konus - Wind (GCN Notices). The source was clearly detected in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2022-03-16 11:25:40.5 UT. The measured peak count rate associated with the burst is 266 (+48, -18) counts/s above the background in the combined data of three quadrants, with a total of 2313 (+321, -294) counts. The local mean background count rate was 361 (+2, -3) counts/s. Using cumulative rates, we measure a T90 of 30 (+6, -4) s. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2022-03-16 11:25:39.22 UT. The measured peak count rate is 887 (+76, -73) counts/s above the background in the combined Veto data of four quadrants, with a total of 4547 (+524, -584) counts. The local mean background count rate was 1454 (+4, -4) counts/s. We measure a T90 of 25 (+5, -2) s from the cumulative Veto light curve. CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb [1]. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. Links: ------ [1] http://astrosat.iucaa.in/czti/?q=grb