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GCN Circular 31408

Subject
GRB 220107A: AstroSat CZTI detection
Date
2022-01-08T05:33:42Z (2 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
A. Suresh (IITB), G. Waratkar (IITB), V. Prasad (IUCAA), 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 220107A, which was
also detected by Fermi-GBM (GCN 31399, 31406), and Swift/BAT-GUANO
(Tohuvavohu et al., GCN 31402) with BALROG localization (Greiner et al.
GCN 31400).

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
2022-01-07 14:46:59.50 UT. The measured peak count rate associated with
the burst is 382 (+36 -38) cts/s above the background in the combined
data of four quadrants, with a total of 4724 (+364 -472) cts. The local
mean background count rate was 149 (+1 -1) cts/s. Using cumulative
rates, we measure a T90 of 97 (+4 -5) 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 2022-01-07 14:46:57.70 UT. The
measured peak count rate is 1451 (+86 -94) cts/s above the background in
the combined Veto data of four quadrants, with a total of 13589 (+1062
-1220) cts. The local mean background count rate was 1500 (+4 -4) cts/s.
We measure a T90 of 87 (+2 -2) 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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