TITLE:   GCN CIRCULAR
NUMBER:  26106
SUBJECT: GRB 191025B: AstroSat CZTI detection
DATE:    19/10/31 18:19:38 GMT
FROM:    Ramkrishna Gaikwad at IUCAA/AstroSat  <ramkrishna@iucaa.in>

R. Gaikwad, S. Gupta, 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 GRB 191025B, which was also detected by Insight-HXMT/HE (Luo Q. et al., GCN #26081), IPN triangulation (Svinkin D. et al., GCN #26086) and Konus-Wind (Kozlova et al., GCN #26089).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with the strongest peak at 2019-10-25 18:42:09.0 UT. The measured peak count rate associated with the burst is 449 cts/s above the background in the combined data of four quadrants, with a total of 567 cts. The local mean background count rate was 514 cts/s. Using cumulative rates, we measure a T90 of 6.9 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.