GCN Circular 31440
Subject
GRB 220111A: AstroSat CZTI detection
Date
2022-01-12T07:34:03Z (3 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 ML pipeline (Abraham et al.,
2021, MNRAS, 504, 3084) and the CIFT framework (Sharma et al., 2021,
JApA, 42, 73), showed detection of a long GRB 220111A, which was also
detected by Fermi-GBM (GCN 31434), with localization reported by BALROG
(Biltzinger et al., GCN 31435).
The source was clearly detected in the 20-200 keV energy range. The
light curve peaks at 2022-01-11 19:21:52.75 UT. The measured peak count
rate associated with the burst is 1028 (+208, -77) cts/s above the
background in the combined data of four quadrants, with a total of 3672
(+250, -232) cts. The local mean background count rate was 471 (+4, -7)
cts/s. Using cumulative rates, we measure a T90 of 10 (+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 2022-01-11
19:21:51.95 UT. The measured peak count rate is 509 (+72, -80) cts/s
above the background in the combined Veto data of four quadrants, with a
total of 1900 (+429, -475) cts. The local mean background count rate was
1580 (+5, -5) cts/s. We measure a T90 of 5 (+6, -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. 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.