[vsnet-grb-info 20802] GRB 180703A: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22900
SUBJECT: GRB 180703A: AstroSat CZTI detection
DATE:    18/07/05 13:40:47 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi at iucaa.in>

V. Sharma, A. Vibhute and D. Bhattacharya (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 180703A, which was also detected by Swift (Evans P. A. et al., GCN 22882), Fermi-LAT (Racusin J. L. et al., GCN 22883), Swift-XRT (Gibson S. L. et al., GCN 22891) and Fermi-GBM (Poolakkil S. et al., GCN 22896).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 21:01:44.5 UT, ~4 s after the GBM trigger. The measured peak count rate is 277.3 cts/s above the background in combined data of four quadrants, with a total of 2182 cts. The local mean background count rate was 519.6 cts/s. Using cumulative rates, we measure a T90 of 20.9 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.