TITLE:   GCN CIRCULAR
NUMBER:  23792
SUBJECT: GRB 190117A: AstroSat CZTI detection
DATE:    19/01/25 03:59:06 GMT
FROM:    Tanazza Khanam at IUCAA  <tanazza@iucaa.in>

T. Khanam, V. Sharma, D. Bhattacharya and  A. Vibhute (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 GRB 190117A, which was also detected by AGILE (MCAL; Ursi, et al., GCN Circ. 23752), Insight (HXMT/HE; Xiao et al., GCN Circ. 23759), Konus-Wind, INTEGRAL (Frederiks D. et al., GCN Circ 23782),  IPN Triangulation (Hurley K. et al., GCN Circ. 23764) and Swift (BAT).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 14:36:49.5 UT. The measured peak count rate is 2356 cts/s above the background in combined data of four quadrants, with a total of 11729 cts. The local mean background count rate was 524 cts/s. Using cumulative rates, we measure a T90 of 22.75 s. In preliminary analysis, we find that 862 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.