{
  "eventId": "GRB 260512A",
  "editedOn": 1778683947310,
  "circularId": 44591,
  "bibcode": "2026GCN.44591....1W",
  "submitter": "Gaurav Waratkar at Caltech <gauravwaratkar@iitb.ac.in>",
  "submittedHow": "web",
  "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 260512A 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 2026-05-12T16:56:43.530 UTC, shows a detection of GRB 260512A, also detected by Fermi/GBM (Fermi GBM Team, GCN 44587).\n\nThe NuSTAR CsI shield data are recorded at 1 Hz. We detect a 10-s long burst consistent with the Fermi/GBM lightcurve. The peak count rate is ~2500-cps with a baseline rate of ~1000-cps during this time period. We do not see evidence in the signal above 100 keV in the CZT detectors.\n\nThe Fermi/GBM localization (GCN 44587) at RA = 153.56, Dec = -82.64 implies an offset from the NuSTAR boresight of 15-deg (i.e. near the boresight) and an offset from the geocenter of 96-deg.\n\nLightcurves and analysis for this GRB can be found here:\nhttps://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2026/260512A  \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",
  "version": 2,
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Gaurav Waratkar at Caltech <gauravwaratkar@iitb.ac.in>",
  "subject": "GRB 260512A: NuSTAR detection of prompt emission",
  "createdOn": 1778629986447,
  "format": "text/plain"
}