Illustration of the half-sheared simulation used to capture the blending shear response. Input secondary galaxies are marked with dashed blue circles, and input primary galaxies with red ones. A subset of the primary galaxies is associated with detections as described in Sect. 3.2, indicated by orange crosses. Two sets of simulations share the same galaxy catalogue and noise realisation, but differ in the shear applied to secondary galaxies: g_s = 0.0 (left panel) and g_s = 0.1 in uncorrelated directions (right panel). Galaxy pairs are identified by finding each secondary galaxy within 10 arcsec of a primary detection found in both simulations. For each pair, the change in the measured shape of the primary galaxy’s detection along the shear direction is calculated between the two simulations, which is used to estimate $R_{\mathrm{blend}}({\mathit{G}}_{\mathrm{p}},{\mathit{G}}_{\mathrm{s}},\theta )$.