R. Gaikwad, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), 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 GRB 190928A, which was also detected by AGILE/MCAL (Ursi A. et al., GCN # 25859), IPN Triangulation (Hurley K. et al., GCN # 25864), CALET Gamma-ray Burst Monitor (Valentin P. et al., GCN # 25865), MASTER optical observations (Lipunov L. et al., GCN # 25867), Konus-Wind observation (Frederiks D. et al., GCN # 25868) and Insight-HXMT/HE (Luo Q. et al., GCN # 25879).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with the strongest peak at 2019-09-28 13:12:16.0 UT. The measured peak count rate associated with the burst is 3601 cts/s above the background in the combined data of four quadrants, with a total of 52582 cts. The local mean background count rate was 494 cts/s. Using cumulative rates, we measure a T90 of 114.6 s. In preliminary analysis, we find that 4621 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.