{
  "eventId": "GRB 260925A",
  "body": "SUBJECT: GRB 260925A: FRAM-Auger optical limit\n\nFilip Novotny, Martin Jelinek and Jan Strobl\n(ASU CAS Ondrejov, CZ),\n\nMartin Masek, Sergey Karpov, Petr Janecek, Jakub Jurysek,\nJan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza\n(Institute of Physics, Prague, CZ)\n\nreport:\n\nThe 30cm robotic telescope FRAM-Auger at the Pierre Auger\nObservatory (Cerro Los Leones, Malargue, Argentina) reacted\nrobotically to the Swift/BAT alert of GRB 260925A (trigger\n1513316, Ambrosi et al., GCN 45739). The field was below the\nhorizon at the time of the trigger; we obtained a series of\n60s R-band images starting at 08:41:36 UT, i.e. ~89 min post\ntrigger, as the field was rising in morning twilight. The first\nimages, taken at elevations of 2-4 deg, are of too poor quality\nto be used. The usable part of the series was obtained between\n08:54:41 and 09:14:59 UT at elevations of 4.4-7.7 deg\n(airmass ~12-7).\n\nWe do not detect any source at the Swift/XRT enhanced position\n(Ambrosi et al., GCN 45739), neither in single images nor in the\ncombined frame, with the following limit:\n\nT-T0[mid]  Images  Span[s]  Limit (Vega)\n~112 min   14      1218     R_C > 15.3\n\nSingle 60s images reach R_C > ~14.\n\nThe photometry is calibrated against the Atlas-REFCAT2\ncatalogue (Tonry et al. 2018, ApJ, 867, 105) and is not\ncorrected for Galactic extinction.",
  "circularId": 45744,
  "createdOn": 1790339479606,
  "submittedHow": "web",
  "format": "text/plain",
  "subject": "GRB 260925A: FRAM-Auger optical limit",
  "submitter": "Filip Novotný at Masaryk University <filip.novotny@talentovani.cz>",
  "eventType": [
    "GRB",
    "Optical Transient"
  ]
}