GCN Circular 21990

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 long-duration bright GRB 171010A, which was also detected by Fermi-GBM (trigger 529354855 / 171010792) and Fermi-LAT (Omodei N. et al, GCN # 21985).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peak emission with strongest peak at 19:01:24.58 UT, ~34 s after the Fermi Trigger. The measured peak count rate is 2001.9 cts/s above the background in combined data of four quadrants, with a total of 61101 cts. The local mean background count rate was 333.1 cts/s. Using cumulative rates, we measure a T90 of 70.3 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.