TITLE: GCN CIRCULAR NUMBER: 28197 SUBJECT: GRB 200801B: AstroSat CZTI detection DATE: 20/08/03 04:37:13 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 a weak detection of a long GRB 200716A, which was also detected by Fermi GBM (GCN #28184) and BALROG (Biltzinge B. et al., GCN #28185) and Global MASTER-Net (Lipunov V. et al., GCN #28195). The source was clearly detected in the 40-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-08-01 15:35:48.939 UT. The measured peak count rate associated with the burst is 112 +/- 16 cts/s above the background in the combined data of four quadrants, with a total of 697 +/- 48 cts. The local mean background count rate was 420 +/- 2 cts/s. Using cumulative rates, we measure a T90 of 17.08 +/- 0.47 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 2020-08-01 15:35:45.558 UT. The measured peak count rate is 327 +/- 37 cts/s above the background in the combined Veto data of four quadrants, with a total of 1598 +/- 87 cts. The local mean background count rate was 1709 +/- 4 cts/s. We measure a T90 of 16.17 +/- 0.26 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, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.