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TITLE:   GCN CIRCULAR
NUMBER:  23395
SUBJECT: GRB 181026A: AstroSat CZTI detection
DATE:    18/10/30 13:23:35 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

T. Khanam (IUCAA), V. Bhalerao (IIT-B), V. Sharma, A. Vibhute and D. Bhattacharya (IUCAA),  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 181026A, which was also detected by Fermi (GBM trigger name: bn181026540) at about 12:57:00.037 UT.

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 12:57:01.50 UT. The measured peak count rate is 251.2 cts/s above the background in combined data of four quadrants, with a total of 2454 cts. The local mean background count rate was 524 cts/s. Using cumulative rates, we measure a T90 of 30.2 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.