GCN Circular 31987
Subject
GRB 220430A: AstroSat CZTI detection
Event
Date
2022-05-02T07:40:42Z (3 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 (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 220430A which was
also reported by Swift (Ambrosi et al., GCN 31972; Osborne et al., GCN
31973; Barthelmy et al., GCN 31981), and AGILE (Ursi et al., GCN 31975).
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
2022-04-30 13:53:58.50 UT. The measured peak count rate associated with
the burst is 892 (+60, -62) counts/s above the background in the
combined data of all the quadrants, with a total of 11896 (+669, -639)
counts. The local mean background count rate was 484 (+2, -2) counts/s.
Using cumulative rates, we measure a T90 of 40 (+4, -2) 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 2022-04-30 13:53:58.52 UT. The
measured peak count rate is 3131 (+109, -98) counts/s above the
background in the combined Veto data of four quadrants, with a total of
48203 (+1134, -1252) counts. The local mean background count rate was
1614 (+3, -5) counts/s. We measure a T90 of 41 (+1, -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