GCN Circular 22688

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 long GRB 180416A, which was also detected by Fermi-GBM (Bissaldi E. et al, GCN # 22644).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 08:10:54.5 UT, ~87 s after GBM trigger. The measured peak count rate is 420.5 cts/s above the background in combined data of four quadrants, with a total of 3904 cts. The local mean background count rate was 508.5 cts/s. Using cumulative rates, we measure a T90 of 92.6 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.