GCN Circular 45783
Subject
GRB 260926C: AstroSat CZTI detection
Event
Date
2026-09-29T10:52:05Z (a day ago)
From
ABHINAV GOYAL at Indian Institute of Technology, Bombay <abhigoyale2003@gmail.com>
Via
Web form
S. Puri (IITB), A. Goyal (IITB), A. Arya (IITB), S. Salunke (IUCAA), Harsha K. H. (IUCAA), G. Waratkar (CalTech/IITB), V. Bhalerao (IITB), A. Vibhute (IUCAA), 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 GRB 260926C which was also detected by Fermi (Fermi GBM team, GCN Circ. 45766), GECAM-B (Luo et al., GCN Circ. 45782).
The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2026-09-26 23:27:11.97 UTC. The measured peak count rate associated with the burst is 58 (+33, -14) counts/s above the background in the combined data of all quadrants, with a total of 214 (+110, -109) counts. The local mean background count rate was 299 (+3, -4) counts/s. Due to poor statistics, we cannot reliably estimate the T90 from it.
The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-09-26 23:27:12.63 UTC.The measured peak count rate associated with the burst is 157 (+48, -32) counts/s above the background in the combined data of all quadrants, with a total of 465 (+163, -201) counts. The local mean background count rate was 685 (+5, -4) counts/s. We measure a T90 of 4 (+2, -2) s from the cumulative Veto light curve.
CZTI data products like interactive and downloadable light curves for this GRB can be found at:
https://astrosat.iucaa.in/cift/cift_products/ET20260926T232712/ET20260926T232712_details.html
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