GCN Circular 28207

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:

The AstroSat CZT Imager recorded a transient event in all four of its CsI anticoincidence (Veto) detectors in the 100-500 keV energy range, coincident with the GRB 200803A reported by Fermi GBM (GCN #28196), Global MASTER-Net (Lipunov V. et al., GCN #28198) Tiled Swift (Evans P. et al., GCN #29200), Fermi-LAT (Cutini S. et al., GCN #29203) and Swift-XRT (Osborne J. et al., GCN #29205). There was no significant detection in the main CZT detectors. 

The light curve showed multiple peaks of emission with the strongest peak at 2020-08-03 03:34:34.825 UT. The measured peak count rate is 444 +/- 46 cts/s above the background in the combined Veto data of four quadrants, with a total of 2872 +/- 42 cts. The local mean background count rate was 1740 +/- 2 cts/s.  We measure a T90 of 17.81 +/- 0.77 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.