{
  "submittedHow": "web",
  "bibcode": "2026GCN.45267....1S",
  "eventType": [
    "GRB",
    "Gamma-ray Transient",
    "X-ray Transient"
  ],
  "format": "text/plain",
  "createdOn": 1785588341341,
  "submitter": "Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>",
  "circularId": 45267,
  "body": "S.Salunke(IUCAA), Harsha K. H. (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:\n\nAnalysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 260731A which was also detected by SVOM (Trigger Num. sb26073115) and Konus-Wind (IPN Notices).\n\nThe source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2026-07-31 23:58:22.466 UTC. The measured peak count rate associated with the burst is 314 (+34, -33) counts/s above the background in the combined data of three quadrants (out of four), with a total of 2019 (+162, -264) counts. The local mean background count rate was 202 (+4, -3) counts/s. We measure a T90 of 11 (+3, -3) s from the cumulative CZT light curve. \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 2026-07-31 23:58:21.203 UTC. The measured peak count rate associated with the burst is 417 (+49, -5) counts/s above the background in the combined data of all quadrants, with a total of 1801 (+233, -234) counts. The local mean background count rate was 591 (+3, -4) counts/s.\nWe measure a T90 of 8 (+4, -2) s from the cumulative Veto light curve.\n\nCZTI data products like interactive and downloadable light curves for this GRB can be found at:https://astrosat.iucaa.in/cift/cift_products/ET20260731T235830/ET20260731T235830_details.html\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",
  "eventId": "GRB 260731A",
  "subject": "GRB 260731A: AstroSat CZTI detection of a long burst"
}