EP241208a: NOT optical upper limits

We observed the field of EP241208a detected by EP-WXT (Wang et al., GCN 38477) and SVOM/ECLAIRs (Atteia et al., GCN 38557) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations started at 02:48:15.84 UT on 2024-12-09, i.e., ~ 10.20 hrs after the EP-WXT trigger, and 5 x 200 s Sloan r- and z- band images were obtained, respectively. No new optical source is found within the ~ 10 arcsec EP-FXT error circle (Wang et al., GCN 38513) after performing image differencing using the DESI Legacy Survey as template, down to the following 3-sigma limits: Filter Tmid-T0 (hr) UL (AB) ------------------------------------------- r 10.35 >23.2 z 10.67 >21.7 calibrated with nearby Pan-STARRS stars and not corrected for Galactic extinction.