Minor-to-major axis ratios as a function of the halo mass (M₂₀₀). Red data points display the median relation for the CDM DMO simulation at z = 0, while the corresponding solid error bars bracket 25 and 75% of the distribution at fixed halo mass. The connected black, blue, green, and magenta data points show the results for the FP runs in different DM models. To avoid overcrowding, they are displayed without the error bars. The left, central, and right panels show the measurements at the halo boundary radius R₂₀₀, R₂₀₀/2, and R₂₀₀/10, respectively. The dot-dashed green curve shows the results from Despali et al. (2014), while the dotted red and black lines show the best-fit relation assuming the median value of the Bonamigo et al. (2015) model at (c/a)_R200 ; this is repeated in all three panels as a guide.