TITLE: GCN CIRCULAR NUMBER: 40272 SUBJECT: EP250427a: Lesedi optical counterpart detection DATE: 25/04/28 13:43:45 GMT FROM: Simon de Wet at University of Cape Town <simdewet@gmail.com> S. de Wet (DTU space), N. Erasmus (SAAO), W.X. Li (NAOC), N.C. Sun (UCAS,NAOC) report: The SAAO 1-m Lesedi telescope located at Sutherland, South Africa, obtained 2x60 s exposures with the Mookodi low-resolution spectrograph and imager in each of the g,r and i bands of EP250427a (Wang et al., GCN 40257) beginning at 00:22:13 UTC on 2025 April 28 (0.87 days post-trigger). We detect the optical counterpart reported by Perez-Garcia et al. (GCN 40259), Liu et al. (GCN 40260), Becerra et al. (GCN 40261), Ghosh et al. (GCN 40263), Brivio et al. (GCN 40264), Chornock et al. (GCN 40265), Saccardi et al. (GCN 40266), Perez-Fournon et al. (GCN 40267), and Xi et al. (GCN 40269) with the following AB magnitudes: g = 20.66 +/- 0.09 r = 20.07 +/- 0.07 i = 19.69 +/- 0.08 Data was taken with the SAAO's 1-m Lesedi robotic telescope with the Mookodi low-resolution spectrograph and imager [1] as part of the SAAO “IO” rapid follow-up program [2]. We thank the SAAO IO team members including N. Erasmus, S. Potter, C. van Gend, H. Worters, S. Chandra, D. Cunnama, M. Hlakola, P. Rabe, R. Julie for making these observations possible. [1] https://doi.org/10.1117/1.JATIS.10.2.025005 [2] https://doi.org/10.1117/12.3015250 View this GCN Circular online at https://gcn.nasa.gov/circulars/40272. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...