[vsnet-grb-info 21205] GRB 180925A: Astrosat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23304
SUBJECT: GRB 180925A: Astrosat CZTI detection
DATE:    18/10/03 18:03:54 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi at iucaa.in>

V. Sharma and T. Khanam (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 180925A, which was also detected by Swift (Gropp J. D. et al., GCN 23268), Insight-HXMT/HE (Luo Q. et al., GCN 23275) and Konus-Wind (Kozlova A. et al., GCN 23291).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 14:37:33.5 UT. The measured peak count rate is 246 cts/s above the background in combined data of four quadrants, with a total of 2223 cts. The local mean background count rate was 506 cts/s. Using cumulative rates, we measure a T90 of around 34.7 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.