Inferred gravitational potential of stellar samples A1-200, A1-300, and A1-400, in the top, middle, and bottom panel, plotted in terms of its square root as a function of z. The width of the blue band shows the 16th to 84th percentile of the inferred posterior density of the respective stellar samples. The band has a lighter colour for z >  Z_lim., indicating that this is an extrapolation outside the spatial volume of the stellar sample. The 1σ band of the expected gravitational potential is shown in grey (identical in all panels). The black dash-dotted and dotted lines show the gravitational potential in case of a homogeneous matter density of 0.2 and 0.1 M_⊙ pc⁻³. Top panel: we also plot the inferred potential of Widmark (2019) in red, where the dot indicates the median and the error bars cover the 10th and 90th percentiles of that work’s eight stellar sample posterior densities.