{
  "eventId": "GRB 261010A",
  "subject": "GRB 261010A: possible optical afterglow detected with the 1.5m OSN",
  "circularId": 45891,
  "submitter": "Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>",
  "submittedHow": "email",
  "body": "F.J. Aceituno, E. J. Fernandez-Garcia, A. J. Castro-Tirado, I. Perez-Garcia, M.D. Caballero-Garcia, M. Gritsevich, S. Guziy (IAA-CSIC) and Y.-D. Hu (GXI), on behalf of a larger collaboration, report:\n\nFollowing the detection of GRB 261010A by both Fermi (Fermi team, GCN 45888) and Swift/BAT (Lien et al. GCN 45889), we triggered the 1.5m telescope at Sierra Nevada Observatory (OSN) in Granada (Spain), starting on Oct 10, 19:49 UT (~32 min post trigger) in the VRI filters. On the coadded image (7x300s, I-band), an uncatalogued object is detected slightly outside the Swift/XRT error circle, on the outskirts of a galaxy visible in the DSS2 archival plate. For the transient we measure a preliminary magnitude of I = 21.0 mag, at coordinates (J2000) = 16:34:59.45 +26:34:57.5, in agreement with the NOT findings (O’Neill et al. GCN 45890). Further observations are needed to confirm its relation to GRB 261010A.\n\nWe thank the staff at OSN for their excellent support.\n\n",
  "createdOn": 1791668559312
}