TITLE: GCN CIRCULAR NUMBER: 27426 SUBJECT: GRB 200318A : AstroSat CZTI detection DATE: 20/03/24 12:17:59 GMT FROM: Soumya Gupta at IUCAA/ASTROSAT S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data showed the detection of a long GRB 200318A, which was also detected by Fermi GBM (GCN #27412).​  The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission peaking at​ 2020-03-18​ 22:35:27​ UT. The measured peak count rate associated with the burst is​ 197 +/- 21.6​ cts/s above the background in the combined data of four quadrants, with a total of​ 990 +/- 48.8​ cts. The local mean background count rate was 566 +/- 3.1 cts/s. Using cumulative rates, we measure a T90 of 10.1 +/- 0.33 s. It was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. 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, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.