GCN Circular 35574
Subject
GRB 240117A: AstroSat CZTI detection
Date
2024-01-19T04:56:39Z (4 months ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
J. Joshi (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 a long-duration GRB 240117A which was also detected by Calet (Trigger Num. 1389556167), Integral-SPIACS (Trigger Num. 10476), and Glowbug (Cheung et al., GCN Circ. 35569).
The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-17 19:52:36.50 UTC. The measured peak count rate associated with the burst is 156 (+35, -30) counts/s above the background in the combined data of three quadrants (out of four), with a total of 451 (+136, -161) counts. The local mean background count rate was 292 (+4, -3) counts/s. Using cumulative rates, we measure a T90 of 3.62 (+3.5, -1.6) s.
The source was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-01-17 19:52:35.72 UTC. The measured peak count rate associated with the burst is 208 (+80, -23) counts/s above the background in the combined data of three quadrants (out of four), with a total of 937 (+206, -219) counts. The local mean background count rate was 1475 (+7, -8) counts/s. We measure a T90 of 5.13 (+0.54, -1.39) 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