[vsnet-grb-info 21402] GRB 181201A: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23501
SUBJECT: GRB 181201A: AstroSat CZTI detection
DATE:    18/12/04 05:29:05 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi at iucaa.in>

T. Khanam, V. Sharma and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), 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 181201A, which was also detected by Integral-IBIS/ISGRI detection (Mereghetti S. et al., GCN 23469), Insight-HXMT/HE detection (Cai C. et al., GCN 23491) and Konus-Wind (Svinkin D. et al., GCN 23495).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 02:39:58.020 UT, ~2 min after the Integral-IBAS trigger. The measured peak count rate is 910.8 cts/s above the background in combined data of four quadrants, with a total of 6099 cts. The local mean background count rate was 569 cts/s. Using cumulative rates, we measure a T90 of 19.2 s. In preliminary analysis, we find that 402 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.