GCN Circular 34472
Subject
GRB 230817A: AstroSat CZTI detection
Date
2023-08-18T05:55:19Z (2 years ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
P. K. Navaneeth (IUCAA), B. Pari (IITB), 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 a long GRB 230817A which was also detected by Fermi (Fermi GBM Team, GCN Circ. 34464).
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 2023-08-17 12:03:31.50 UTC. The measured peak count rate associated with the burst is 470 (+48, -40) counts/s above the background in the combined data of all quadrants, with a total of 7321 (+420, -529) counts. The local mean background count rate was 418 (+2, -2) counts/s. Using cumulative rates, we measure a T90 of 48 (+6, -7) s. In the preliminary analysis, we find 537 Compton events associated with this event.
The source 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 2023-08-17 12:03:31.31 UTC. The measured peak count rate associated with the burst is 361 (+80, -24) counts/s above the background in the combined data of all quadrants, with a total of 4084 (+1006, -1452) counts. The local mean background count rate was 1322 (+5, -4) counts/s. We measure a T90 of 33 (+9, -5) 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