TITLE:   GCN CIRCULAR
NUMBER:  28045
SUBJECT: GRB 200629A: AstroSat CZTI detection
DATE:    20/06/30 17:34:42 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 200629A, which was also detected by BALROG (Biltzinger B. et al., GCN #28039), Fermi GBM (GCN #28040) and Global MASTER-Net (Lipunov V. et al., GCN # 28041). 

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 2020-06-29 12:49:53.599 UT. The measured peak count rate associated with the burst is 337 +/- 28 cts/s above the background in the combined data of four quadrants, with a total of 3117 +/- 32 cts. The local mean background count rate was 486 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 27.14 +/- 0.12 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 2020-06-29 12:49:52.574 UT. The measured peak count rate is 310 +/- 33 cts/s above the background in the combined Veto data of four quadrants, with a total of 2105 +/- 42 cts. The local mean background count rate was 1414 +/- 1 cts/s. We measure a T90 of 21.01 +/- 0.20 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.