Inner density slopes of compressed halos. Left: The best-fit inner slopes of the compressed DM halo profiles versus effective surface mass density. For galaxies with a bulge, the value of Υ_⋆ is chosen as Υ_bulge. Filled points show galaxies that are fit by compressed halos, color coded by their fit qualities. Open points are galaxies for which our fitting procedure fails, so we compressed initial NFW halos determined by ΛCDM priors. Right: density slopes measured at 1.5% R₂₀₀ plotted against stellar-to-halo mass ratio. The blue region shows the density slope within 1 σ scatter expected from hydrodynamic simulations of galaxy formation with strong stellar feedback (Tollet et al. 2016). Dark grey and light grey regions show the expected slopes of NFW halos for the SPARC galaxies according to their concentrations with and without considering the 1σ scatter, respectively. Open points have the same meaning as in the left panel.