reasons already indicated.

[Haloes]{} vs. Sub[haloes]{} {#Ssec:HvsS}
----------------------------

So far we have seen that the lower spin parameter distribution observed for sub[haloes]{} appears to be a robust result that does not depend upon the choice of halo finder, gravitational softening or mass resolution. Here we explore a possible physical origin for the lower subhalo spins.

![The Peebles (upper) and Bullock (lower) spin distribution of [<span style="font-variant:small-caps;">subfind</span>]{} (sub-)[haloes]{} at $z=0$. The colored solid histograms show the results for sub[haloes]{}, and black dashed histogram for [haloes]{}. Two lines show the best fitting functions from @bullock_2001 (black dashed line) and @onions_2013 (red solid line). Only (sub-)[haloes]{} with at least 300 particles have been included. For total numbers refer to [Table \[tab:haloes\]]{}.[]{data-label="pic1"}](Histo_L_Subfind_Peebles "fig:"){width="1\linewidth"}\
![The Peebles (upper) and Bullock (lower) spin distribution of [<span style="font-variant:small-caps;">subfind</span>]{} (sub-)[haloes]{} at $z=0$. The colored solid histograms show the results for sub[haloes]{}, and black dashed histogram for [haloes]{}. Two lines show the best fitting functions from @bullock_2001 (black dashed line) and @onions_2013 (red solid line). Only (sub-)[haloes]{} with at least 300 particles have been included. For total numbers refer to [Table \[tab:haloes\]]{}.[]{data-label="pic1"}](Histo_L_Subfind_Bullock "fig:"){width="1\linewidth"}

The left and right panel of [Figure \[pic1\]]{} show the Peebles spin and Bullock spin distributions of 