GCN Circular 28620

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 detection of a long GRB 201013A, which was also detected by Swift (Page K. et al., GCN #28607), Swift-XRT (Beardmore A. et al., GCN #28608), Global MASTER-Net (Lipunov V. et al., GCN #28612), Swift/UVOT (Breeveld A. et al., GCN #28613), Swift-BAT (Laha S. et al., GCN #28614), FRAM-ORM (Jelinek M. et al., GCN #28615) and CALET (Tamura T. et al., GCN #28618).

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 2020-10-13 03:46:32.000 UT. The measured peak count rate associated with the burst is 631 +/- 39 cts/s above the background in the combined data of four quadrants, with a total of 3054 +/- 43 cts. The local mean background count rate was  586 +/- 17 cts/s. Using cumulative rates, we measure a T90 of 11.08 +/- 0.03 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 2020-10-13 03:46:29.500 UT. The measured peak count rate is 1229 +/- 53 cts/s above the background in the combined Veto data of four quadrants, with a total of 4458 +/- 55 cts. The local mean background count rate was 1131 +/- 22  cts/s. We measure a T90 of 11.63 +/- 0.01 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.