[vsnet-grb-info 19097] GRB 170207A: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20642
SUBJECT: GRB 170207A: AstroSat CZTI detection
DATE:    17/02/09 14:36:07 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 a clear detection of GRB170207A (IPN Triangulation detection: D. Svinkin et al., GCN Circ. 20628) in the 40-200 keV energy range. The light curve shows multiple peaks. The first peak occurred at 21:45:08.67 UT, 5 s after the Fermi trigger (Fermi GBM detection: O.J. Roberts., GCN circular 20630) and a second group of peaks was detected 18 s after the trigger. An interval of ~ 5 s between these two showed no detectable emission. The measured peak count rate is 345 counts/s above the background in combined data of four quadrants, with a total 2332.5 counts. The local mean background count rate was 352 counts/s. Using cumulative rates, we measure a T90 of 36.5 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.