Core of Abell 370 from BUFFALO data (F814/F606/F435 filters). The cyan circles correspond to the location of the four DM clumps from N23, and the magenta circles show their locations from model (ii) (Sect. 3.5). We draw in yellow the critical curve for z = 2 generated from model (ii). The white squares show the location of each clump in the mass model with three DM clumps (Sect. 5). The green ellipses show the cluster members that were optimised individually. We show in red the Lyman-α emitters from Claeyssens et al. (2022), for which we computed a magnification (Sect. 7). North is up, and east is left. The horizontal bar represents 20″, which corresponds to ∼100 kpc at the redshift of Abell 370.