TITLE: GCN CIRCULAR NUMBER: 18422 SUBJECT: GRB 151006A: Astrosat CZTI detection DATE: 15/10/16 11:28:09 GMT FROM: Varun Bhalerao at IUCAA V. Bhalerao (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration: Analysis of Astrosat commissioning data showed the presence of GRB 151006A (Kocevski et al. 2015, GCN 18398) in the Cadmium Zinc Telluride Imager. The source was located 60.7 degrees away from the pointing direction and was detected at energies above 60 keV. Modelling the profile as a fast rise and exponential decay, we measure T90 of 65s, 75s, and 50s in 60-80 keV, 80-100 keV and 100-250 keV bands respectively. In addition, the GRB is clearly detected in a lightcurve created from double events satisfying Compton scattering criteria (Vadawale et al., 2015, A&A, 578, 73). This demonstrates the feasibility of measuring polarisation for brighter GRBs with CZTI.