{
  "eventId": "GRB 231118A",
  "submittedHow": "web",
  "createdOn": 1700372535965,
  "submitter": "Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>",
  "subject": "GRB 231118A: AstroSat CZTI detection",
  "circularId": 35116,
  "bibcode": "2023GCN.35116....1N",
  "body": "P. K. Navaneeth (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:\n\nAnalysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 231118A which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35100), and Swift-BAT (Laha et al., GCN Circ. 35101).\n\nThe source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2023-11-18 17:16:33.55 UTC. The measured peak count rate associated with the burst is 773 (+165, -131) counts/s above the background in the combined data of three quadrants (out of four), with a total of 885 (+229, -215) counts. The local mean background count rate was 237 (+5, -8) counts/s. Using cumulative rates, we measure a T90 of 3.9 (+1.6, -1.0) s.\n\nThe source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-11-18 17:16:32.74 UTC. The measured peak count rate associated with the burst is 638 (+71, -77) counts/s above the background in the combined data of all quadrants, with a total of 1634 (+436, -460) counts. The local mean background count rate was 1222 (+9, -10) counts/s. We measure a T90 of 3.7 (+1.8, -1.3) s from the cumulative Veto light curve.\n\nCZTI 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.\n\nCZTI GRB detections are reported regularly on the payload site at:\nhttp://astrosat.iucaa.in/czti/?q=grb\n"
}