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 a long GRB 220609B which was
also detected by CALET GBM (Asaoka et al., GCN Circ. 32185).
The source was clearly detected in the 20-200 keV energy range. The
light curve peaks at 2022-06-09 12:21:15.65 UTC. The measured peak count
rate associated with the burst is 1230 (+239, -53) counts/s above the
background in the combined data of four quadrants, with a total of 6095
(+298, -291) counts. The local mean background count rate was 411 (+3,
-6) counts/s. Using cumulative rates, we measure a T90 of 11 (+1, -1) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve peaks at 2022-06-09
12:21:15.42 UTC. The measured peak count rate is 4988 (+127, -136)
counts/s above the background in the combined Veto data of four
quadrants, with a total of 24547 (+545, -597) counts. The local mean
background count rate was 1421 (+5, -5) counts/s. We measure a T90 of 11
(+2, -1) 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.