Cross-correlation signal-to-noise maps of H₂O, CO, Fe, and Mg in the atmosphere of WASP-121 b. The dashed vertical and horizontal white lines represent the stellar V_sys (38.12 km s⁻¹, from Line-by-line Artigau et al. 2022) and K_p (216.8 km s⁻¹, calculated from results in Bourrier et al. 2020) of WASP-121 b, respectively. Tentative signals of H₂O, OH, Fe and Mg can be seen near the expected orbital position of WASP-121 b.