TITLE:   GCN CIRCULAR
NUMBER:  22363
SUBJECT: GRB 180113A: AstroSat CZTI detection
DATE:    18/01/20 18:19:33 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 bright GRB 180113A, which was also detected by Swift (Ukwatta T. N. et al., GCN 22325), Fermi-GBM (Veres P. et al., GCN 22328), Konus-Wind (Frederiks D. et al., GCN 22344) and CALET (Torii S. et al., GCN 22359).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 02:47:07.500 UT, ~1.5 s after the Swift-BAT trigger. The measured peak count rate is 345 cts/s above the background in combined data of four quadrants, with a total of  2536 cts. The local mean background count rate was 628 cts/s. Using cumulative rates, we measure a T90 of 14.3 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.