TITLE:   GCN CIRCULAR
NUMBER:  24753
SUBJECT: GRB 190604A: AstroSat CZTI detection
DATE:    19/06/05 15:59:32 GMT
FROM:    Prachee Ghumatkar at IUCAA/AstroSat  <prachee@iucaa.in>

P. Ghumatkar, V. Sharma, D. Bhattacharya, T. Khanam and A. Vibhute (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 190604A, which was also detected by Fermi GBM (GCN #24739), BALROG localization (Biltzinger B. et al., GCN #24740) and Global MASTER-Net (Lipunov V. et al., GCN #24741).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with the strongest peak at 10:42:41.5 UT. The measured peak count rate associated with the burst is 874 cts/s above the background in the combined data of four quadrants, with a total of 5755 cts. The local mean background count rate was 508 cts/s. Using cumulative rates, we measure a T90 of 13.55 s. In preliminary analysis, we find that 460 Compton events are associated with this event.

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.