TITLE:   GCN CIRCULAR
NUMBER:  29881
SUBJECT: GRB 210419B: AstroSat CZTI detection
DATE:    21/04/22 10:55:41 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb@iitb.ac.in>

P. Sawant (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), S. Gupta (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al, 2020, arxiv:2011.07067) showed detection of a long GRB 210419B, which was also detected by Fermi-GBM (GCN #29831).

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed a broad emission peak with the strongest peak at 2021-04-19 21:10:25.625 UT. The measured peak count rate is 1623 (+4 ,-4) cts/s above the background in the combined Veto data of four quadrants, with a total of 3054 (+641, -726) cts. The local mean background count rate was 181 (+89, --3) cts/s. We measure a T90 of 35 (+9, -12) s from the cumulative Veto light curve.

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