GCN Circular 32028

R. Gopalakrishnan (IUCAA), V. Prasad (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 
CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed detection of GRB 220511A which was also 
reported by Fermi GBM (GCN #32018), AGILE (Ursi et al., GCN #32021), and 
Swift/BAT-GUANO (DeLaunay et al., GCN #32023).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaked at 2022-05-11 13:41:57.45 UT. The measured peak count 
rate associated with the burst is  802 (+197, -74) counts/s above the 
background in the combined data of four quadrants, with a total of 1126 
(+156, -184) counts. The local mean background count rate was 525 (+9, 
-9) counts/s. Using cumulative rates, we measure a T90 of 1.8 (+0.8, 
-0.4) 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.