TITLE: GCN CIRCULAR NUMBER: 42804 SUBJECT: GRB 251122A / EP251122a: LCO optical upper limits DATE: 25/11/22 16:36:43 GMT FROM: SVOM_group <svomgroup@bao.ac.cn> A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud), L. P. Xin (NAOC), D. Turpin, J. T. Palmerio (CEA/Irfu), C. Wu (NAOC), B. Cordier (CEA/Irfu), Z.-Y. Lin, C. Lachaud (APC), report on behalf of the SVOM mission team: We observed the field of GRB 251122A / EP251122a detected by SVOM/ECLAIRs (Lin et al. GCN 42800) and EP/WXT (Wang et al., GCN 42799) with the LCO 1m telescope at the Siding Spring Observatory equipped with the Sinistro instrument. Our observation started at 2025-11-22T14:56:27 (UTC) about 1 hour after the trigger. We obtained 3x200 s exposures in each of the SDSS r and Pan-STARRS z filters. The r-band images are unfortunately trailed, which reduces our sensitivity. In the stacked images, we do not detect any new optical source within the EP/FXT and SVOM/MXT error circles. We measure the following 3-sigma upper limits calibrated against the Pan-STARRS catalog, and not corrected for Galactic extinction: r > 20.8 AB (mid time 80 min after the SVOM T0); z > 20.4 AB (mid time 63 min after the SVOM T0). Our results are consistent with the limits reported by Wu et al. (GCN 42801). We do not detect the candidate counterpart reported by Cheng et al. (GCN 42803), which is fainter and reported at an earlier epoch than our observations. This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/42804. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...