Left: Variation of the average 3D axis ratio, q=b/a, with bound dark matter particle number for the three resolutions for both the HYDRO (solid) and DMO (transparent) runs. Right: The variation of the average 3D axis ratio with bound halo dark matter mass for the three resolutions for both the HYDRO and DMO runs. The different colours indicate the different simulation resolutions, with m₈ being the highest resolution. There is a downturn at below 10³ particles (which corresponds to a different mass for each resolution as is clear from the right panel) which suggests its origin is numerical rather than physical. The DM masses for the HYDRO runs have been corrected by a factor of Ω_m/(Ω_m−Ω_b). The errors are calculated for each particle number (or mass) bin by taking the standard deviation in each bin and dividing by the square root of the number of objects in that bin.