V. Prasad (IUCAA), P. Sawant (IUCAA), G. Waratkar (IITB), A. Vibhute
(IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao
(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al.,
2021, JApA, 42, 73) showed detection of a long GRB 211120A, which was
also detected by GECAM (Li et al., GCN 31100).
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
2021-11-20 23:05:22.85 UT. The measured peak count rate associated with
the burst is 1756 (+251, -174) cts/s above the background in the
combined data of two quadrants, with a total of 2263 (+183, -134) cts.
The local mean background count rate was 443 (+4, -8) cts/s. Using
cumulative rates, we measure a T90 of 4.8 (+0.6, -0.2) 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.