TITLE: GCN CIRCULAR NUMBER: 43205 SUBJECT: EP251222a: GSP Optical Counterpart Detection DATE: 25/12/23 05:56:12 GMT FROM: Wenxiong Li at NAOC W. X. Li, S. J. Xue (NAOC); M. Andrews, J. Farah, D. A. Howell, C. McCully, and Kathryn Wynn (Las Cumbres Observatory), on behalf of a larger collaboration, report optical follow-up observations of EP251222a (Huang et al. GCN 43200) obtained with a Las Cumbres Observatory (LCO) 1-m telescope at at the Cerro Tololo Inter-American Observatory in Chile, ~12.5 hours after the EP-WXT trigger. We acquired 2 × 300 s exposures using the broad optical w band. Within the EP-FXT error region, we found that the source at R.A. = 62.5025, Dec. = –1.4792 brightened, increasing in brightness from r = 22.9 mag (DESI Legacy Survey) to r = 21.6 mag, with no other optical counterpart detected. These observations were taken as part of the Global Supernova Project (GSP).