TITLE: GCN CIRCULAR NUMBER: 23012 SUBJECT: GRB 180715A: AstroSat CZTI detection DATE: 18/07/22 14:53:11 GMT FROM: Vidushi Sharma at IUCAA 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 GRB 180715A, which was also detected by Swift (Palmer D. et al., GCN 22947), Fermi-GBM (Hamburg R. et. al., GCN 22952) and CALET (Torii S. et al.,GCN 22956). The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 18:06:59.5 UT. The measured peak count rate is 403.6 cts/s above the background in combined data of four quadrants, with a total of 408 cts. The local mean background count rate was 476.4 cts/s. Using cumulative rates, we measure a T90 of 0.9 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.