GCN Circular 34492
Subject
GRB 230818A: AstroSat CZTI detection
Date
2023-08-19T17:14:33Z (9 months ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
B. Pari (IITB), P. K. Navaneeth (IUCAA), G. Waratkar (IITB), 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 GRB 230818A which was also detected by Fermi-GBM (Fermi GBM Team, GCN Circ. 34478) and Swift-BAT (Tohuvavohu et al., GCN Circ. 34479).
The source was detected in the 20-200 keV energy range in two quadrants. The light curve peaks at 2023-08-18 23:27:37.5 UTC. The measured peak count rate associated with the burst is 96.6 (+28.4, -24.9) counts/s above the background in the combined data of two quadrants, with a total of 372 (+89, -104) counts. The local mean background count rate was 198.2 (+2.1, -3.3) counts/s. Using cumulative rates, we measure a T90 of 6.3 (+2.1, -1.9) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-08-18 23:27:37.3 UTC. The measured peak count rate associated with the burst is 356.8 (+79.6, -44.8) counts/s above the background in the combined data of all quadrants, with a total of 2027 (+489, -526) counts. The local mean background count rate was 1569.3 (+11.3, -12.1) counts/s. We measure a T90 of 10.0 (+3.6, -4.3) 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