Halo mass functions for the range in σ₈ (left) and Ω_m (right), over the mass range 10^12.8 − 10^13.6 M_⊙, as allowed by the cosmological parameter constraints from Planck Collaboration VI (2020). Halo mass functions were calculated using Colossus (Diemer 2018), assuming the Crocce et al. (2010) mass function model . The bottom plot shows how the strong lensing cross-section area changes as a function of the halo mass in the relevant region, calculated from a lens with M_h = 10¹³ M_⊙, M_* = 10^11.5 M_⊙, α_SPS = 1.2, and γ_DM = 1.3, with a half-light radius of R_e = 10 kpc, at z = 1. The test source is placed at z = 2.5.