TITLE:   GCN CIRCULAR
NUMBER:  28060
SUBJECT: GRB 200703B: AstroSat CZTI detection
DATE:    20/07/04 10:25:02 GMT
FROM:    Soumya Gupta at IUCAA/ASTROSAT  <soumya@iucaa>

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 200703B, which was also detected by Fermi GBM (GCN #28059).

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 2020-07-03 23:17:06.531 UT. The measured peak count rate associated with the burst is 226 +/- 23 cts/s above the background in the combined data of four quadrants, with a total of 3165 +/- 66 cts. The local mean background count rate was 585 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 31.58 +/- 0.35 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 2020-07-03 23:17:09.576 UT. The measured peak count rate is 733 +/- 42 cts/s above the background in the combined Veto data of four quadrants, with a total of 8880 +/- 119 cts. The local mean background count rate was 1808 +/- 2 cts/s.  We measure a T90 of 31.945 +/- 0.209 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.