GCN Circular 32441

R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), 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 220803A which was also 
detected by Fermi-GBM (TrigNum: 681212354) and was reported in an 
IPN_RAW Notice (contributed by Konus-Wind).

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 
2022-08-03 09:39:10.15 UTC. The measured peak count rate associated with 
the burst is 714 (+175, -87) counts/s above the background in the 
combined data of three (out of four) quadrants, with a total of 935 
(+238, -226) counts. The local mean background count rate was 349 (+5, 
-6) counts/s. Using cumulative rates, we measure a T90 of 3.9 (+4.3, 
-1.0) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2022-08-03 
09:39:09.32 UTC. The measured peak count rate is 274 (+72, -76) counts/s 
above the background in the combined Veto data of all quadrants, with a 
total of 842 (+310, -330) counts. The local mean background count rate 
was 1691 (+8, -9) counts/s. We measure a T90 of 6 (+2, -4) 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.