TITLE:   GCN CIRCULAR
NUMBER:  20324
SUBJECT: GRB 161218B: Astrosat CZTI detection
DATE:    16/12/21 18:20:09 GMT
FROM:    Vedant Kumar at Astrosat/CZTI/IUCAA  <vedant@iucaa.in>

V. Kumar, D. Bhattacharya and V. Bhalerao (IUCAA), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed clear detection of a long duration and bright GRB161218B (Fermi-GBM detection: Hamburg et al., GCN 20286) 
in the 40-200 keV energy range. The light curve shows multiple peak structure with at least 4 clear peaks and main peak at 08:32:42.0 UT followed
by a weaker emission, 1.35 secs after the Fermi- GBM trigger(consistent with GCN 20286). The measured peak count rate is 738.478 counts/sec above
the background in combined data of four quadrants, with a total of 6025.78 counts. The local mean background count rate was 328.52 counts/sec. 
Using cumulative rates, we measure a T90 of 29.0 sec.

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.