GCN Circular 33479
Subject
GRB 230313A: AstroSat CZTI detection
Date
2023-03-15T03:17:07Z (a year ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
A. Ahmad (IITB), G. Waratkar (IITB), P K. Navaneeth (IUCAA), A. Vibhute
(IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/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 the detection of a long GRB 230313A which was
also detected by Fermi GBM (GCN Circ. 33467).
The source was faintly detected in the 20-200 keV energy range. The
light curve peaks at 2023-03-13 11:38:43.9 UTC. The measured peak count
rate associated with the burst is 211.1 (+167.6 -9.9) counts/s above the
background in the combined data of three quadrants (out of four), with a
total of 259 (+104 -110) counts. The local mean background count rate
was 371.0 (+8.7 -8.6) counts/s. Using cumulative rates, we measure a T90
of 3.68 (+0.61 -2.44) s.
It was also faintly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve peaks at 2023-03-13
11:38:43.2 UTC. The measured peak count rate is 270.4 (+59.6 -65.5)
counts/s above the background in the combined Veto data of three
quadrants (out of four), with a total of 463 (+172 -181) counts. The
local mean background count rate was 1116.0 (+5.4 -6.4) counts/s. We
measure a T90 of 4.28 (+1.18 -3.20) s from the cumulative Veto light
curve.
CZTI is built by a TIFR-led consortium of institutes across India,
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research
Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb