TITLE:   GCN CIRCULAR
NUMBER:  22681
SUBJECT: GRB 180416B: AstroSat CZTI detection
DATE:    18/05/04 17:30:55 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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 180416B, which was also detected by CALET (Kawakubo Y. et al., GCN 22653) along with Fermi-GBM (trigger #545609416) and Konus-Wind trigger time on 22:10:10.60 UT.

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 22:10:12.50 UT. The measured peak count rate is 388 cts/s above the background in combined data of four quadrants, with a total of 5491 cts. The local mean background count rate was 526.8 cts/s. Using cumulative rates, we measure a T90 of 56.3 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.