TITLE: GCN CIRCULAR NUMBER: 45485 SUBJECT: GRB 260829A: AstroSat CZTI detection DATE: 26/09/01 11:39:37 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com> A. Goyal (IITB), A. Arya (IITB), Harsha K. H. (IUCAA), S. Salunke(IUCAA), G. Waratkar (CalTech/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 GRB 260829A which was also detected by Fermi (Fermi GBM team, GCN Circ. 45464), BALROG localization (Preis et.al., GCN Circ. 45465), GECAM-B (Hao-Xuan Guo et al., GCN Circ. 45470), and IPN triangulation (Kozyrev et.al., GCN Circ. 45476). The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-08-29 06:08:31.7 UTC. The measured peak count rate associated with the burst is 614 (+58, -62) counts/s above the background in the combined data of all quadrants, with a total of 2357 (+429, -471) counts. The local mean background count rate was 643 (+6, -6) counts/s. We measure a T90 of 13.1 (+5.3, -6.5) s from the cumulative Veto light curve. 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 2026-08-29 06:08:30.7 UTC. The measured peak count rate associated with the burst is 213 (+34, -27) counts/s above the background in the combined data of three quadrants (out of four), with a total of 708 (+180, -194) counts. The local mean background count rate was 227 (+2, -3) counts/s. Due to poor statistics, we cannot reliably estimate the T90 from it. CZTI data products like interactive and downloadable light curves for this GRB can be found at: https://astrosat.iucaa.in/cift/cift_products/525679702.67/S525679702.67_deta... 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/45485. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...