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GCN Circular 32193

Subject
GRB 220610B: AstroSat CZTI detection
Date
2022-06-12T04:01:10Z (2 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
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 220610B which was 
also detected by INTEGRAL SPI-ACS (TrigNum 9952.0) and Fermi-GBM 
(TrigNum 676537486).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2022-06-10 07:04:43.50 UTC. The measured peak count 
rate associated with the burst is 125 (+32, -20) counts/s above the 
background in the combined data of two quadrants (out of four), with a 
total of 969 (+230, -221) counts. The local mean background count rate 
was 226 (+2, -2) counts/s. Using cumulative rates, we measure a T90 of 
20 (+7, -8) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2022-06-10 
07:04:43.38 UTC. The measured peak count rate is 388 (+69, -71) counts/s 
above the background in the combined Veto data of four quadrants, with a 
total of 2179 (+368, -491) counts. The local mean background count rate 
was 1471 (+5, -5) counts/s. We measure a T90 of 13 (+5, -3) 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.
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