Stellar bars are the most common non-axisymmetric structures in galaxies and their impact on the evolution of disc galaxies at all cosmological times can be significant .
Classical theory predicts that stellar discs are stabilized against bar formation if embedded in massive spheroidal dark matter halos .
However , dark matter halos have been shown to facilitate the growth of bars through resonant gravitational interaction .
Still , it remains unclear why some galaxies are barred and some are not .
In this study , we demonstrate that co-rotating ( i.e. , in the same sense as the disc rotating ) dark matter halos with spin parameters in the range of 0 \leq \lambda _ { \mathrm { dm } } \leq 0.07 - which are a definite prediction of modern cosmological models - promote the formation of bars and boxy bulges and therefore can play an important role in the formation of pseudobulges in a kinematically hot dark matter dominated disc galaxies .
We find continuous trends for models with higher halo spins : bars form more rapidly , the forming slow bars are stronger , and the final bars are longer .
After 2 Gyrs of evolution , the amplitude of the bar mode in a model with \lambda _ { \mathrm { dm } } = 0.05 is a factor of \sim 6 times higher , A _ { 2 } / A _ { 0 } = 0.23 , than in the non-rotating halo model .
After 5 Gyrs , the bar is \sim 2.5 times longer .
The origin of this trend is that more rapidly spinning ( co-rotating ) halos provide a larger fraction of trailing dark matter particles that lag behind the disc bar and help growing the bar by taking away its angular momentum by resonant interactions .
A counter-rotating halo suppresses the formation of a bar in our models .
We discuss potential consequences for forming galaxies at high-redshift and present day low mass galaxies which have converted only a small fraction of their baryons into stars .