GCN Circular 27890
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 weak detection of a long GRB 200604A, which was also detected by Fermi GBM (GCN #27887) and Global MASTER-Net (Lipunov V. et al., GCN # 27888). 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 2020-06-04 20:00:02.520 UT. The measured peak count rate associated with the burst is 174 +/- 26 cts/s above the background in the combined data of four quadrants, with a total of 780 +/- 20 cts. The local mean background count rate was 516 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 12.77 +/- 0.06 s. In preliminary analysis, we find that 605 Compton events are associated with this event. 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.