{
  "subject": "GRB 250101A: LCOGT optical afterglow detection",
  "bibcode": "2025GCN.38769....1E",
  "eventId": "GRB 250101A",
  "format": "text/plain",
  "submittedHow": "web",
  "circularId": 38769,
  "submitter": "Ismael Perez-Fournon at Instituto de Astrofisica de Canarias <ipf@iac.es>",
  "body": "P. Escudero-Coca, B. Armas-Chinea, F. Dobrindt, G. Fernández-Rodríguez, Á. García Lozano, A. Huertas Ferrer, C. Méndez-Lapido, I. Ortega-Casas, M. Torreiro Martínez, G. Villa (ULL), S.R. Berlanas, F. Poidevin, and I. Pérez-Fournon (IAC and ULL)\n\nWe report on optical imaging of the field of GRB 250101A, discovered by Swift BAT (Page et al., GCN #38752), with the Las Cumbres Observatory global telescope network (LCOGT) 40-cm telescope located at the LCOGT node at Sutherland Observatory (South Africa). The observation, a single 600-sec exposure in the SDSS r' filter, started on 2025-01-01 19:56:30 UT, i.e. ~ 6.56 hr after the Swift BAT trigger. We detect the optical afterglow at a position consistent with the Swift UVOT position reported by Page et al. (GCN #38752). We measure a magnitude of r' = 19.96 +/- 0.16 calibrated against PanSTARRS DR1 stars and not corrected for Galactic extinction.\n\nThis result is consistent with other reports: Li et al., GCN 38753; Mohan et al., GCN 38754; Zhu et al., GCN 38755; Budnev et al., GCN 38756; Wu et al., GCN 38758; Moskvitin and Spiridonova, GCN 38762;\nOdeh and Guessoum, GCN 38763; Hu et al., GCN 38764; and D'Avino and Izzo, GCN 38768.\n\nA rebrightening in the optical has been reported by Moskvitin et al. (GCN 38765).\n\nThe spectroscopic redshift of z = 2.49 has been obtained by Zhu et al. (GCN 38759).\n\nThese results are based on observations made with the Las Cumbres Observatory’s education network \ntelescopes that were upgraded through generous support from the Gordon and Betty Moore Foundation \nand are part of a course on Astrophysical Techniques of the Master in Astrophysics of the Universidad \nde La Laguna, Tenerife, Spain (LCOGT observing programme IAC2024B-010, ULL-ASTRO-MASTER).\n",
  "createdOn": 1735776946191
}