[vsnet-grb-info 19717] GRB 170805A: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21502
SUBJECT: GRB 170805A: AstroSat CZTI detection
DATE:    17/08/17 08:49:43 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi at iucaa.in>

V. Sharma (IUCAA), V. Bhalerao (IITB), 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 clear detection of short GRB 170805A (Insight-HXMT detection: Ma X. et al, GCN Circ. 21421) in the 40-200 keV energy range. The light curve shows single peak emission at 14:38:34.70 UT, around ~0.7 s before the Insight-HXMT trigger. The measured peak count rate is 4917.1 counts/s above the background in combined data of four quadrants, with a total 22361 counts. The local mean background count rate was 372.9 counts/s. Using cumulative rates, we measure a T90 of 0.96 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.