TITLE: GCN CIRCULAR NUMBER: 27716 SUBJECT: GRB 200510A: AstroSat CZTI detection DATE: 20/05/11 19:50:59 GMT FROM: Soumya Gupta at IUCAA/ASTROSAT S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (IUCAA/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 200510A, which was also detected by Fermi GBM (GCN #27711) and BALROG (Kunzweiler F. et al.,GCN #27712). The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peak of emission with the strongest peak at 2020-05-10 10:41:16.542 UT. The measured peak count rate associated with the burst is 310 +/- 27 cts/s above the background in the combined data of four quadrants, with a total of 967 +/- 10 cts. The local mean background count rate was 496 +/- 1.0 cts/s. Using cumulative rates, we measure a T90 of 9.29 +/- 0.005 s. It was also clearly 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.