GCN Circular 31788

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 220324A which was
also detected by Fermi - GBM (Trigger Number - 669782349).

The source was clearly detected in the 20-200 keV energy range. The
light curve peaks at 2022-03-24 02:39:09.50 UT. The measured peak count
rate associated with the burst is 200 (+44, -28) counts/s above the
background in the combined data of all four quadrants, with a total of
2304 (+346, -331) counts. The local mean background count rate was 502
(+2, -2) counts/s. Using cumulative rates, we measure a T90 of 22 (+5,
-4) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve showed a single peak of
emission at 2022-03-24 02:38:00.95 UT. The measured peak count rate is
169 (+83, -10) counts/s  above the background in the combined Veto data
of four quadrants, with a total of 1428 (+566, -627) counts. The local
mean background count rate was 1687 (+5, -6) counts/s. We measure a T90
of 18 (+5, -9) 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