GCN Circular 33033

M. Dixit (IITB), G. Waratkar (IITB), R. Gopalakrishnan (IUCAA), A. 
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka 
University/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., 
2021, JApA, 42, 73) showed the detection of GRB 221203C which was also 
detected by KONUS-Wind (reported in GCN Notices).

The source was detected in the CsI anticoincidence (Veto) detector in 
the 100-500 keV energy range. The light curve peaks at 2022-12-03 
17:40:54.0 UTC. The measured peak count rate is 393.6 (+69.9, -74.5) 
counts/s above the background in the combined Veto data of all 
quadrants, with a total of 1483 (+379, -412) counts. The local mean 
background count rate was 1466.2 (+5.3, -6.2) counts/s. We measure a T90 
of 9.10 (+5.86, -4.66) 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, URSC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.