TITLE: GCN CIRCULAR NUMBER: 22901 SUBJECT: GRB 180704A: AstroSat CZTI detection DATE: 18/07/05 13:41:47 GMT FROM: Vidushi Sharma at IUCAA V. Sharma, A. Vibhute 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 180704A, which was also detected by Swift-BAT (Sonbas E. et al., GCN 22885) and Swift-XRT (Burrows D. N. et al., GCN 22887). The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 05:36:43.500 UT. The measured peak count rate is 660.2 cts/s above the background in combined data of four quadrants, with a total of 5324 cts. The local mean background count rate was 571.8 cts/s. Using cumulative rates, we measure a T90 of 26 s. In preliminary analysis, we find that 463 compton events are associated with this event. 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.