{
  "circularId": 42688,
  "subject": "GRB 251113A: AstroSat CZTI detection",
  "bibcode": "2025GCN.42688....1G",
  "eventId": "GRB 251113A",
  "body": "A. Goyal (IITB), A. Arya (IITB), S. Salunke (IUCAA), M. Tembhurnikar (IUCAA), Harsha K. H. (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:\n\nAnalysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 251113A which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 42671).\n\nThe source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-11-13 17:37:42.84 UTC. The measured peak count rate associated with the burst is 208 (+40, -21) counts/s above the background in the combined data of all quadrants, with a total of 2657 (+431, -393) counts. The local mean background count rate was 269 (+4, -5) counts/s. Using cumulative rates, we measure a T90 of 23 (+2, -5) 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 2025-11-13 17:37:42.35 UTC. The measured peak count rate associated with the burst is 350 (+68, -53) counts/s above the background in the combined data of all quadrants, with a total of 4325 (+900, -914) counts. The local mean background count rate was 1169 (+11, -11) counts/s. We measure a T90 of 22 (+2, -4) 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",
  "createdOn": 1763155627063,
  "submitter": "Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>",
  "submittedHow": "web",
  "format": "text/plain"
}