V. Sharma (IUCAA), V. Bhalerao (IIT-B), D. Bhattacharya (IUCAA), A. R. Rao (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 180809B, which was also detected by Swift (Moss M. J. et al., GCN 23105), CALET (Cherry M. L. et al., GCN 23116) and Konus-Wind (Svinkin D. et al., GCN 23128).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 20:29:23.500 UT. The measured peak count rate is 2562 cts/s above the background in combined data of four quadrants, with a total of 38208 cts. The local mean background count rate was 501 cts/s. Using cumulative rates, we measure a T90 of 44.1 s. In preliminary analysis, we find that 3257 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.
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.