TITLE: GCN CIRCULAR NUMBER: 44640 SUBJECT: EP260514a: NOT optical counterpart confirmation DATE: 26/05/16 07:51:09 GMT FROM: liuxing@nao.cas.cn X. Liu, Z.P. Zhu, J. An, S.Q. Jiang, L.B. He, D. Xu (NAOC), S.Y. Fu (HUST), J.P.U. Fynbo (DAWN/NBI), L. Fuglsang, A. S. Martensson（NOT）report: We observed the field of EP260514a detected by EP/WXT (Cheng et al., GCN 44613; Lipunov et al., GCN 44614; Mohan et al., GCN 44619; Sánchez et al., GCN 44632; Li et al., GCN 44638; Liu et al., GCN 44639) using the 2.56m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observation started at 2026-05-15 23:05:35 UT, i.e., about 1.26 days post-burst, and 4x300s r-band frames were obtained. The optical counterpart candidate (Liu et al., GCN 44639) has decayed to r = 23.1 +/- 0.1 in our stacked image at a median time of 1.26 days post-trigger, calibrated with Pan-STARRS DR2 stars in the field and not corrected for Galactic extinction. Its coordinares are improved as R.A.(J2000)= 14:17:10.49 Dec.(J2000)= +49:22:31.4 with an uncertainty of ~0.5 arcsec. No optical source could be detected in the Legacy DR10 image at the corresponding coordinates, down to a limiting magnitude of r ~ 24.3. We thus think the source is likely the optical counterpart of EP260514a. View this GCN Circular online at https://gcn.nasa.gov/circulars/44640. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...