[vsnet-grb-info 27715] GRB 210411B: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29818
SUBJECT: GRB 210411B: AstroSat CZTI detection
DATE:    21/04/15 14:46:58 GMT
FROM:    Gaurav Waratkar at IIT Bombay  <gauravwaratkar24 at gmail.com>

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 210411B, which was also
detected by Fermi-GBM (GCN #29792).

The source was clearly detected in the 20-200 keV energy range. The light
curve showed multiple peaks of emission with the strongest peak at
2021-04-11 13:32:55.50 UT. Quadrant D was noisy, and we exclude it from
further analysis. The measured peak count rate associated with the burst is
117 (+47, -13) cts/s above the background in the combined data of four
quadrants, with a total of 1409 (+320, -296) cts. The local mean background
count rate was 492 (+2, -2) cts/s. Using cumulative rates, we measure a T90
of 27 (+4, -5) s.

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.