GCN Circular 32183

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 detection of a long GRB 220608A which was 
also reported by Fermi GBM (GCN 32178
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 ).

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 
2022-06-08 05:03:45.50 UTC. The measured peak count rate associated with 
the burst is 294 (+43, -35) counts/s above the background in the 
combined data of three quadrants, with a total of 2720 (+389, -365) 
counts. The local mean background count rate was 393 (+1, -2) counts/s. 
Using cumulative rates, we measure a T90 of 36 (+11, -3) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve showed multiple peaks 
of emission with the strongest peak at 2022-06-08 05:03:44.45 UTC. The 
measured peak count rate is 483 (+71, -70) counts/s above the background 
in the combined Veto data of four quadrants, with a total of 4040 (+617, 
-645) counts. The local mean background count rate was 1621 (+4, -4) 
counts/s. We measure a T90 of 36 (+5, -10) 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.