[vsnet-grb-info 19605] GRB 170702A: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21348
SUBJECT: GRB 170702A: AstroSat CZTI detection
DATE:    17/07/15 20:38:55 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi at iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IITB), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed clear detection of GRB 170702A (CALET Gamma-Ray Burst Monitor detection: Ozawa S. et al, GCN Circ. 21334) in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 23:41:36.0 UT, around ~2 s after the CALET trigger. The measured peak count rate is 1192.5 counts/s above the background in combined data of four quadrants, with a total 3911 counts. The local mean background count rate was 334.5 counts/s. Using cumulative rates, we measure a T90 of 8.7 s.

It was clearly detected in the CsI anticoincidence detector (Veto) also as bright detection 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.