[vsnet-grb-info 20636] GRB 180505A: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22734
SUBJECT: GRB 180505A: AstroSat CZTI detection
DATE:    18/05/16 12:23:40 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi at iucaa.in>

V. Sharma (IUCAA), V. Bhalerao (IIT-B), 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 the detection of a long GRB 180505A, which was also detected by Fermi-GBM (Malacaria E. et al, GCN # 22689).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 12:57:30.50 UT, ~11 s after GBM trigger. The measured peak count rate is 772.4 cts/s above the background in combined data of four quadrants, with a total of 3643 cts. The local mean background count rate was 697.6 cts/s. Using cumulative rates, we measure a T90 of 22.8 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.