{
  "circularId": 44653,
  "createdOn": 1778975949420,
  "submittedHow": "email",
  "bibcode": "2026GCN.44653....1J",
  "submitter": "Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>",
  "subject": "GRB 260516D: FRAM-ORM optical limit",
  "body": "Martin Jelinek, Filip Novotny and Jan Strobl (ASU CAS Ondrejov, CZ),\nSergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek, Jan Ebr, \nRonan Cunniffe, Petr Travnicek and Michael Prouza\n(Institute of Physics, Prague, CZ)\n\nreport:\n\nThe 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted\nrobotically to the SVOM/ECLAIRs alert of GRB 260516D (Brunet et al.,\nGCNC 44649), obtaining a series of unfiltered 60s images starting at\n20:54:16 UT, i.e. ~948s post trigger.\n\nWe do not detect any new or strongly variable source in comparison\nto the ATLAS REFCAT2 catalog. In single images the detection limit\ngradually improved from R_C > 17.1 in the first frame (midtime ~978s \npost trigger), stabilizing at R_C > ~18.3–18.4 around ~2000s post\ntrigger and remaining there for the rest of the ~one hour sequence.\nCombining images in groups of 10 (10x60s), we reach limits of R_C >\n~20 (R_C > ~19.3 for the first combined frame).\n\n",
  "eventId": "GRB 260516D"
}