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GCN Circular 31180

Subject
GRB 211206A: AstroSat CZTI detection
Date
2021-12-07T10:12:35Z (2 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
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 a long GRB 211206A which was
also detected by AGILE/MCAL (Ursi et al., GCN 31175) and Swift/BAT-GUANO
(DeLaunay et al., GCN 31176). 

The source was clearly detected in the 20-200 keV energy range. The
light curve peaks at 2021-12-06 19:51:12.450 UT. The measured peak count
rate associated with the burst is 776 (+198, -60) cts/s above the
background in the combined data of two quadrants, with a total of 1947
(+221, -223) cts. The local mean background count rate was 443 (+7, -10)
cts/s. Using cumulative rates, we measure a T90 of 4.3 (+1.3, -0.6) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve peaks at 2021-12-06
19:51:12.088 UT. The measured peak count rate is 1509 (+86, -95) cts/s
above the background in the combined Veto data of four quadrants, with a
total of 5582 (+310, -365) cts. The local mean background count rate was
1466 (+4, -4) cts/s. We measure a T90 of 6.6 (+1.5, -1.6) 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 [1]. 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. 

Links:
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[1] http://astrosat.iucaa.in/czti/?q=grb
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