GCN Circular 28216

S. Gupta, V. Sharma, A. Vibhute 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 200806A, which was also detected by Swift (Ambrosi E. et al., GCN #28211), Global MASTER-Net (Lipunov V. et al., GCN #28212) and Swift-XRT (Beardmore A. et al., GCN #28214).

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 2020-08-06 15:29:11.500 UT. The measured peak count rate associated with the burst is 665 +/- 33 cts/s above the background in the combined data of four quadrants, with a total of 5023 +/- 36 cts. The local mean background count rate was 402 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 33.93 +/- 0.05 s. In the preliminary analysis, we find that 636 Compton events are associated with this event.

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 2020-08-06 15:29:10.000 UT. The measured peak count rate is 987 +/- 50 cts/s above the background in the combined Veto data of four quadrants, with a total of 6708 +/- 67 cts. The local mean background count rate was 1506 +/- 1 cts/s.  We measure a T90 of 33.68 +/- 0.13 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.