TITLE: GCN CIRCULAR NUMBER: 43108 SUBJECT: GRB 251213A: AstroSat CZTI detection DATE: 25/12/15 06:37:41 GMT FROM: Gaurav Waratkar at Caltech <gauravwaratkar@iitb.ac.in> Harsha K. H. (IUCAA), S. Salunke (IUCAA), M. Tembhurnikar (IUCAA), A. Arya (IITB), A. Goyal (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 CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 251213A which was also detected by GECAM-B (Wang et. al., GCN Circ. 43106). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-12-13 12:30:11.00 UTC. The measured peak count rate associated with the burst is 48 (+18, -9) counts/s above the background in the combined data of three quadrants (out of four), with a total of 617 (+188, -211) counts. The local mean background count rate was 187 (+1, -2) counts/s. Using cumulative rates, we measure a T90 of 39 (+1, -14) s. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2025-12-13 12:30:12.01 UTC. The measured peak count rate associated with the burst is 265 (+71, -15) counts/s above the background in the combined data of all quadrants, with a total of 3624 (+653, -519) counts. The local mean background count rate was 1137 (+4, -6) counts/s. We measure a T90 of 36 (+1, -2) 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/43108. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...