Mean virial surface luminosities of Lyα (erg s⁻¹ kpc⁻², left) and UV (erg s⁻¹ Hz⁻¹ kpc⁻², right) as a function of LAE multiplicity. Normalization is based on the area defined by the mean R₂₀₀ of the host halo. Black: TNG100-true; pink: TNG100-identified; cyan: ODIN-COSMOS; blue: halos without LAEs (see explanation in the text). Solid, dashed, and dotted lines correspond to z = 2.4, z = 3.1, and z = 4.5, respectively. Error bars show the standard error of the mean in each bin.