TITLE: GCN CIRCULAR NUMBER: 32441 SUBJECT: GRB 220803A: AstroSat CZTI detection DATE: 22/08/04 11:25:47 GMT FROM: Gaurav Waratkar at IIT,Bombay R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/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 the detection of GRB 220803A which was also detected by Fermi-GBM (TrigNum: 681212354) and was reported in an IPN_RAW Notice (contributed by Konus-Wind). 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 2022-08-03 09:39:10.15 UTC. The measured peak count rate associated with the burst is 714 (+175, -87) counts/s above the background in the combined data of three (out of four) quadrants, with a total of 935 (+238, -226) counts. The local mean background count rate was 349 (+5, -6) counts/s. Using cumulative rates, we measure a T90 of 3.9 (+4.3, -1.0) s. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2022-08-03 09:39:09.32 UTC. The measured peak count rate is 274 (+72, -76) counts/s above the background in the combined Veto data of all quadrants, with a total of 842 (+310, -330) counts. The local mean background count rate was 1691 (+8, -9) counts/s. We measure a T90 of 6 (+2, -4) 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. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.