{
  "subject": "GRB 260730B: NuSTAR detection of prompt emission",
  "submitter": "Gaurav Waratkar at Caltech <gauravwaratkar@iitb.ac.in>",
  "body": "G. Waratkar (Caltech) and B. Grefenstette (Caltech) report on behalf of the NuSTAR Search for INteresting Gamma-ray Signals (SINGS) working group:\n\nThe NuSTAR SINGS working group reports the detection of prompt emission from the long-duration GRB 260730B in both the NuSTAR CsI anti-coincidence shields. Details of the search algorithm will be described in a future paper.\n\nThe NuSTAR SINGS algorithm, triggered at 2026-07-30T13:13:45.0 UTC, shows a detection of GRB 260730B, also detected by SVOM-GRM (GCN notices). \n\nThe NuSTAR CsI shield data are recorded at 1 Hz. We detect a single episode with two peaks lasting for about 25-s. The peak count rate is ~3500-cps with a baseline rate of ~1000-cps during this time period. We also see a signal above 100 keV in the CZT detectors.\n\nLightcurves and analysis for this GRB can be found here:\nhttps://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2026/260730B \n\nInformation on NuSTAR SINGS can be found here: \nhttps://nustarsoc.caltech.edu/NuSTAR_Public/grbs/     \n\nNuSTAR is a NASA Small Explorer mission led by Caltech and managed by JPL for NASA's Science Mission Directorate in Washington.\n",
  "eventId": "GRB 260730B",
  "eventType": [
    "GRB",
    "X-ray Transient"
  ],
  "submittedHow": "web",
  "circularId": 45262,
  "bibcode": "2026GCN.45262....1W",
  "createdOn": 1785466695496,
  "format": "text/plain"
}