TITLE: GCN CIRCULAR NUMBER: 27994 SUBJECT: GRB 200619B: AstroSat CZTI detection DATE: 20/06/19 21:25:55 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 200619B, which was also detected by Fermi GBM (GCN #27986). The source was clearly detected in the 40-200 keV energy range. The light curve showed a single peak of emission peaking at 2020-06-19 11:48:43.617 UT. The measured peak count rate associated with the burst is 188 +/- 23 cts/s above the background in the combined data of four quadrants, with a total of 917 +/- 11 cts. The local mean background count rate was 520 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 8.182 +/- 0.028 s. 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.