TITLE: GCN CIRCULAR NUMBER: 35551 SUBJECT: GRB 240115B: AstroSat CZTI detection DATE: 24/01/17 07:19:29 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar24@gmail.com> 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 240115B which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35540), and INTEGRAL (S.Mereghetti et al., GCN Circ. 35541). 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 2024-01-15 16:45:40.50 UTC. The measured peak count rate associated with the burst is 80 (+42, -5) counts/s above the background in the combined data of three quadrants (out of four), with a total of 2052 (+489, -339) counts. The local mean background count rate was 280 (+1, -4) counts/s. Using cumulative rates, we measure a T90 of 47 (+7, -4) s. The source was also 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 2024-01-15 16:46:04.75 UTC. The measured peak count rate associated with the burst is 127 (+72, -1) counts/s above the background in the combined data of three quadrants (out of four), with a total of 1941 (+685, -748) counts. The local mean background count rate was 1168 (+5, -5) counts/s. We measure a T90 of 36 (+6, -10) 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/35551. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...