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 bright GRB 180305A, which was also detected by Fermi/GBM (Veres P. et al., GCN 22458), Konus-Wind (Svinkin D. et al., GCN 22461), Swift/XRT (D'Avanzo P. et al., GCN 22462) and CALET (Penacchioni A. V. et al., GCN 22467).
The source was clearly detected in the 40-200 keV energy range. The light curve shows single peak emission with strongest peak at 09:26:12.5 UT, ~4 s after Fermi/GBM trigger. The measured peak count rate is 427.3 cts/s above the background in combined data of four quadrants, with a total of 2358 cts. The local mean background count rate was 490.6 cts/s. Using cumulative rates, we measure a T90 of 8.9 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.