TITLE: GCN CIRCULAR NUMBER: 44713 SUBJECT: EP260526a: LCO optical upper limits DATE: 26/05/27 12:19:35 GMT FROM: Agnes van Hoof at Radboud University <agnes.vanhoof@ru.nl> A. P. C. van Hoof (Radboud), R. A. J. Eyles-Ferris (Leicester), J. Quirola-Vasquez (Radboud), P. G. Jonker (Radboud), D. B. Malesani (DAWN/NBI and Radboud), J. A. Chacón (PUC), F. E. Bauer (SSI and UTA), report on behalf of a larger collaboration: We observed the field of the X-ray transient EP260526a (Yang et al, GCN 44712) using LCO 1m telescopes located at the Cerro Tololo observatory equipped with SINISTRO instruments. A series of 5x300 s exposures were taken using the SDSS-r filter and 3x300 s using the SDSS-z filter, starting on 2026-05-27 at 08:07:52 UT (i.e., ~1.4 days after the first X-ray detection). No new source is detected within the EP/WXT uncertainty region compared with the Legacy and Pan-STARRS surveys. From the stacked images, we obtain the following 3-sigma upper limits, consistent with those reported by Becerra et al. (GCN 44710): r > 22.5 z > 20.6 These upper limits are in AB magnitudes, calibrated using nearby stars from the Pan-STARRS catalogue, and are not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44713. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...