TITLE: GCN CIRCULAR NUMBER: 44503 SUBJECT: GRB 260506B: AstroSat CZTI detection DATE: 26/05/08 19:22:25 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com> S. Salunke (IUCAA), Harsha K. H. (IUCAA), M. Tembhurnikar (IUCAA), A. Goyal (IITB), A. Arya (IITB), 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 CIFT2 framework showed the detection of GRB 260506B which is also detected by the Fermi/GBM (Fermi GBM team, GCN Circ. 44484). The source was clearly 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 2026-05-06 13:07:41.9 UTC. The measured peak count rate associated with the burst is 129 (+37, -17) counts/s above the background in the combined data of all four quadrants, with a total of 899 (+239, -328) counts. The local mean background count rate was 289 (+2, -3) counts/s. Using cumulative rates, we measure a T90 of 22 (+12, -15) s. We caution that there is a 0.3 s dead time in the CZTI data in the burst, hence the actual T90 may be slightly longer. 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 2026-05-06 13:07:42.0 UTC. The measured peak count rate associated with the burst is 440 (+67, -69) counts/s above the background in the combined data of all quadrants, with a total of 3325 (+520, -551) counts. The local mean background count rate was 1313 (+4, -4) counts/s. We measure a T90 of 36 (+3, -7) 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 data products like interactive and downloadable light curves for this GRB can be found at: https://astrosat.iucaa.in/cift/cift_products/515768858.51/S515768858.51_deta... 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/44503. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...