TITLE: GCN CIRCULAR NUMBER: 43056 SUBJECT: EP251118a / GRB 251118C: VLT/MUSE redshift confirmation DATE: 25/12/09 17:24:40 GMT FROM: Andrea Saccardi at CEA/Irfu <andrea.saccardi@cea.fr> A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud), L. Izzo (INAF/OACn & DARK/NBI), V. D’Elia (ASI/SSDC), J. An, D. Xu (NAOC), M. De Pasquale (U. of Messina) report on behalf of the Stargate collaboration: We observed the field of EP251118a / GRB 251118C detected by EP (Jiang et al., GCN 42749; Shi et al., GCN 42754), Konus-Wind (Frederiks et al., GCN 42765), SVOM/GRM (Wang et al., GCN 42766), Swift/BAT (Delaunay et al., GCN 42770), and Glowbug (Woolf et al., GCN 42771), using the ESO VLT UT4 (Yepun) equipped with the MUSE spectrograph. Our observation started at 07:17:25 UT on 2025 November 19 (14.6 hr after the GRB trigger), and consisted of 3 exposures of 700 s each. The optical counterpart (Malesani et al., GCN 42751; Lipunov et al., GCN 42755; Belkin et al., GCN 42758; Yadav et al., GCN 42760; Busmann et al., GCN 42763; Francile et al., GCN 42767; Urquijo-Rodríguez et al., GCN 42773; Li et al., GCN 42776; Lee et al., GCN 42780; Moskvitin and Spiridonova, GCN 42785; Gupta et al., GCN 42787; Liu et al., GCN 42793; Aryan et al., GCN 42798; Gupta et al., GCN 42810; Volnova et al., GCN 42926) is well detected in the wavelength-stacked “white light” image. Our spectra cover the wavelength range 4750 - 9330 AA. In a preliminary reduction, we detect a continuum over the entire covered wavelength range. From the detection of several absorption features that we identify as Fe II, Mg II, Mg I, and Ca II, we infer a redshift of z = 1.217 for the GRB. Additionally, we note the presence of the [O II] 3726,3729 doublet in emission at a comparable redshift (z = 1.218). Our result is thus fully consistent with, and improves, the value previously reported by the Nordic Optical Telescope (An et al., GCN 42756). We acknowledge expert support from the observing staff in Paranal, in particular Cedric Ledoux, Fuyan Bian, and Juan Carlos Olivares. View this GCN Circular online at https://gcn.nasa.gov/circulars/43056. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...