GCN Circular 25687

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 190901A, which was also detected by Fermi GBM Final Real-time Localization (GCN #25601), BALROG localization (Biltzinger B. et al., GCN #25602), Global MASTER-Net (Lipunov V. et al., GCN #25603), Insight-HXMT/HE (Yao J. M. et al., GCN # 25646).

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 2019-09-01 21:21:49.0 UT. The measured peak count rate associated with the burst is 215 cts/s above the background in the combined data of four quadrants, with a total of 891 cts. The local mean background count rate was 572 cts/s. Using cumulative rates, we measure a T90 of 13.4 s.

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.